21737845784640 has 448 divisors, whose sum is σ = 74435402096640. Its totient is φ = 5357474242560.

The previous prime is 21737845784581. The next prime is 21737845784693. The reversal of 21737845784640 is 4648754873712.

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors.

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 63 ways as a sum of consecutive naturals, for example, 266573314 + ... + 266654846.

Almost surely, 2^{21737845784640} is an apocalyptic number.

21737845784640 is a gapful number since it is divisible by the number (20) 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 21737845784640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37217701048320).

21737845784640 is an abundant number, since it is smaller than the sum of its proper divisors (52697556312000).

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

21737845784640 is a wasteful number, since it uses less digits than its factorization.

21737845784640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81930 (or 81920 counting only the distinct ones).

The product of its (nonzero) digits is 252887040, while the sum is 66.

The spelling of 21737845784640 in words is "twenty-one trillion, seven hundred thirty-seven billion, eight hundred forty-five million, seven hundred eighty-four thousand, six hundred forty".