21705600765 has 24 divisors (see below), whose sum is σ = 36892018080. Its totient is φ = 10895358208.

The previous prime is 21705600737. The next prime is 21705600767. The reversal of 21705600765 is 56700650712.

It is not a de Polignac number, because 21705600765 - 2⁸ = 21705600509 is a prime.

It is a super-2 number, since 2×21705600765² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21705600767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2499195 + ... + 2507864.

It is an arithmetic number, because the mean of its divisors is an integer number (1537167420).

Almost surely, 2^21705600765 is an apocalyptic number.

It is an amenable number.

21705600765 is a deficient number, since it is larger than the sum of its proper divisors (15186417315).

21705600765 is a wasteful number, since it uses less digits than its factorization.

21705600765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5007101 (or 5007084 counting only the distinct ones).

The product of its (nonzero) digits is 88200, while the sum is 39.

The spelling of 21705600765 in words is "twenty-one billion, seven hundred five million, six hundred thousand, seven hundred sixty-five".