21539378840616 has 192 divisors, whose sum is σ = 71830568584320. Its totient is φ = 5678132866560.

The previous prime is 21539378840591. The next prime is 21539378840641. The reversal of 21539378840616 is 61604887393512.

21539378840616 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 9 + 3 + 7 + 8 + 8 + 4 + 0 + 616 = 666.

It is an interprime number because it is at equal distance from previous prime (21539378840591) and next prime (21539378840641).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13687926 + ... + 15180186.

It is an arithmetic number, because the mean of its divisors is an integer number (374117544710).

It is a 1-persistent number, because it is pandigital, but 2⋅21539378840616 = 43078757681232 is not.

Almost surely, 2^{21539378840616} is an apocalyptic number.

21539378840616 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21539378840616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35915284292160).

21539378840616 is an abundant number, since it is smaller than the sum of its proper divisors (50291189743704).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21539378840616 is a wasteful number, since it uses less digits than its factorization.

21539378840616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1494496 (or 1494489 counting only the distinct ones).

The product of its (nonzero) digits is 52254720, while the sum is 63.

The spelling of 21539378840616 in words is "twenty-one trillion, five hundred thirty-nine billion, three hundred seventy-eight million, eight hundred forty thousand, six hundred sixteen".