21456205155 has 256 divisors, whose sum is σ = 52553318400. Its totient is φ = 8025937920.

The previous prime is 21456205051. The next prime is 21456205193. The reversal of 21456205155 is 55150265412.

21456205155 is a `hidden beast` number, since 2 + 14 + 5 + 620 + 5 + 15 + 5 = 666.

It is not a de Polignac number, because 21456205155 - 2¹⁰ = 21456204131 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 4061806 + ... + 4067084.

It is an arithmetic number, because the mean of its divisors is an integer number (205286400).

Almost surely, 2^21456205155 is an apocalyptic number.

21456205155 is an abundant number, since it is smaller than the sum of its proper divisors (31097113245).

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

21456205155 is a wasteful number, since it uses less digits than its factorization.

21456205155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5351 (or 5345 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 36.

The spelling of 21456205155 in words is "twenty-one billion, four hundred fifty-six million, two hundred five thousand, one hundred fifty-five".