21051707760 has 80 divisors (see below), whose sum is σ = 72511445280. Its totient is φ = 5613788160.

The previous prime is 21051707759. The next prime is 21051707777. The reversal of 21051707760 is 6770715012.

21051707760 is a `hidden beast` number, since 2 + 10 + 517 + 0 + 77 + 60 = 666.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21051707760² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 4870921 + ... + 4875240.

It is an arithmetic number, because the mean of its divisors is an integer number (906393066).

Almost surely, 2^21051707760 is an apocalyptic number.

21051707760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21051707760 is an abundant number, since it is smaller than the sum of its proper divisors (51459737520).

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

21051707760 is a wasteful number, since it uses less digits than its factorization.

21051707760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9746183 (or 9746171 counting only the distinct ones).

The product of its (nonzero) digits is 20580, while the sum is 36.

The spelling of 21051707760 in words is "twenty-one billion, fifty-one million, seven hundred seven thousand, seven hundred sixty".