21297086757 has 40 divisors (see below), whose sum is σ = 33539283360. Its totient is φ = 13430435040.

The previous prime is 21297086687. The next prime is 21297086771. The reversal of 21297086757 is 75768079212.

It is a happy number.

It is not a de Polignac number, because 21297086757 - 2¹¹ = 21297084709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21297086777) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1041007 + ... + 1061267.

It is an arithmetic number, because the mean of its divisors is an integer number (838482084).

Almost surely, 2^21297086757 is an apocalyptic number.

21297086757 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21297086757 is a deficient number, since it is larger than the sum of its proper divisors (12242196603).

21297086757 is a wasteful number, since it uses less digits than its factorization.

21297086757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20975 (or 20966 counting only the distinct ones).

The product of its (nonzero) digits is 2963520, while the sum is 54.

The spelling of 21297086757 in words is "twenty-one billion, two hundred ninety-seven million, eighty-six thousand, seven hundred fifty-seven".