21371749776 has 160 divisors (see below), whose sum is σ = 68936421120. Its totient is φ = 6289975296.

The previous prime is 21371749757. The next prime is 21371749813. The reversal of 21371749776 is 67794717312.

21371749776 is a `hidden beast` number, since 2 + 13 + 71 + 7 + 497 + 76 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

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 31 ways as a sum of consecutive naturals, for example, 46440 + ... + 211896.

It is an arithmetic number, because the mean of its divisors is an integer number (430852632).

Almost surely, 2^21371749776 is an apocalyptic number.

21371749776 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 21371749776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34468210560).

21371749776 is an abundant number, since it is smaller than the sum of its proper divisors (47564671344).

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

21371749776 is a wasteful number, since it uses less digits than its factorization.

21371749776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165510 (or 165498 counting only the distinct ones).

The product of its digits is 3111696, while the sum is 54.

The spelling of 21371749776 in words is "twenty-one billion, three hundred seventy-one million, seven hundred forty-nine thousand, seven hundred seventy-six".