21697053756 has 48 divisors (see below), whose sum is σ = 57867828480. Its totient is φ = 6198192000.

The previous prime is 21697053737. The next prime is 21697053757. The reversal of 21697053756 is 65735079612.

It is a junction number, because it is equal to n+sod(n) for n = 21697053699 and 21697053708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21697053757) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 656631 + ... + 688881.

It is an arithmetic number, because the mean of its divisors is an integer number (1205579760).

Almost surely, 2^21697053756 is an apocalyptic number.

It is an amenable number.

21697053756 is an abundant number, since it is smaller than the sum of its proper divisors (36170774724).

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

21697053756 is a wasteful number, since it uses less digits than its factorization.

21697053756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40274 (or 40272 counting only the distinct ones).

The product of its (nonzero) digits is 2381400, while the sum is 51.

The spelling of 21697053756 in words is "twenty-one billion, six hundred ninety-seven million, fifty-three thousand, seven hundred fifty-six".