21568542045156 has 72 divisors (see below), whose sum is σ = 55994893489080. Its totient is φ = 6995092179456.

The previous prime is 21568542044989. The next prime is 21568542045157. The reversal of 21568542045156 is 65154024586512.

21568542045156 is a `hidden beast` number, since 2 + 1 + 5 + 6 + 8 + 542 + 0 + 45 + 1 + 56 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 9966547976256 + 11601994068900 = 3156984^2 + 3406170^2 .

It is not an unprimeable number, because it can be changed into a prime (21568542045157) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 151319890 + ... + 151462358.

It is an arithmetic number, because the mean of its divisors is an integer number (777706854015).

Almost surely, 2^{21568542045156} is an apocalyptic number.

It is an amenable number.

21568542045156 is an abundant number, since it is smaller than the sum of its proper divisors (34426351443924).

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

21568542045156 is a wasteful number, since it uses less digits than its factorization.

21568542045156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256173 (or 256168 counting only the distinct ones).

The product of its (nonzero) digits is 11520000, while the sum is 54.

The spelling of 21568542045156 in words is "twenty-one trillion, five hundred sixty-eight billion, five hundred forty-two million, forty-five thousand, one hundred fifty-six".