21365506577155 has 32 divisors (see below), whose sum is σ = 27681239013120. Its totient is φ = 15737408319360.

The previous prime is 21365506577123. The next prime is 21365506577209. The reversal of 21365506577155 is 55177560556312.

It is a happy number.

It is not a de Polignac number, because 21365506577155 - 2⁵ = 21365506577123 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21365506577155.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41335944 + ... + 41849626.

It is an arithmetic number, because the mean of its divisors is an integer number (865038719160).

Almost surely, 2^{21365506577155} is an apocalyptic number.

21365506577155 is a deficient number, since it is larger than the sum of its proper divisors (6315732435965).

21365506577155 is a wasteful number, since it uses less digits than its factorization.

21365506577155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515331.

The product of its (nonzero) digits is 33075000, while the sum is 58.

The spelling of 21365506577155 in words is "twenty-one trillion, three hundred sixty-five billion, five hundred six million, five hundred seventy-seven thousand, one hundred fifty-five".