21540076957 has 4 divisors (see below), whose sum is σ = 24617230816. Its totient is φ = 18462923100.

The previous prime is 21540076951. The next prime is 21540076963. The reversal of 21540076957 is 75967004512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21540076951) and next prime (21540076963).

It is a cyclic number.

It is not a de Polignac number, because 21540076957 - 2³ = 21540076949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540076951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1538576919 + ... + 1538576932.

It is an arithmetic number, because the mean of its divisors is an integer number (6154307704).

Almost surely, 2^21540076957 is an apocalyptic number.

It is an amenable number.

21540076957 is a deficient number, since it is larger than the sum of its proper divisors (3077153859).

21540076957 is an equidigital number, since it uses as much as digits as its factorization.

21540076957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3077153858.

The product of its (nonzero) digits is 529200, while the sum is 46.

The spelling of 21540076957 in words is "twenty-one billion, five hundred forty million, seventy-six thousand, nine hundred fifty-seven".