21697932672 has 448 divisors, whose sum is σ = 72171576960. Its totient is φ = 6449725440.

The previous prime is 21697932653. The next prime is 21697932673. The reversal of 21697932672 is 27623979612.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21697932673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 37604448 + ... + 37605024.

It is an arithmetic number, because the mean of its divisors is an integer number (161097270).

Almost surely, 2^21697932672 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21697932672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36085788480).

21697932672 is an abundant number, since it is smaller than the sum of its proper divisors (50473644288).

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

21697932672 is an equidigital number, since it uses as much as digits as its factorization.

21697932672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 653 (or 626 counting only the distinct ones).

The product of its digits is 3429216, while the sum is 54.

The spelling of 21697932672 in words is "twenty-one billion, six hundred ninety-seven million, nine hundred thirty-two thousand, six hundred seventy-two".