21540076956 has 36 divisors (see below), whose sum is σ = 56465142552. Its totient is φ = 7180025328.

The previous prime is 21540076951. The next prime is 21540076963. The reversal of 21540076956 is 65967004512.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11079315 + ... + 11081258.

It is an arithmetic number, because the mean of its divisors is an integer number (1568476182).

Almost surely, 2^21540076956 is an apocalyptic number.

It is an amenable number.

21540076956 is an abundant number, since it is smaller than the sum of its proper divisors (34925065596).

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

21540076956 is a wasteful number, since it uses less digits than its factorization.

21540076956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22160592 (or 22160578 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 45.

The spelling of 21540076956 in words is "twenty-one billion, five hundred forty million, seventy-six thousand, nine hundred fifty-six".