21021533155 has 32 divisors (see below), whose sum is σ = 29041689600. Its totient is φ = 14309032320.

The previous prime is 21021533147. The next prime is 21021533191. The reversal of 21021533155 is 55133512012.

It is not a de Polignac number, because 21021533155 - 2³ = 21021533147 is a prime.

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, 3207592 + ... + 3214138.

It is an arithmetic number, because the mean of its divisors is an integer number (907552800).

Almost surely, 2^21021533155 is an apocalyptic number.

21021533155 is a deficient number, since it is larger than the sum of its proper divisors (8020156445).

21021533155 is a wasteful number, since it uses less digits than its factorization.

21021533155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7219.

The product of its (nonzero) digits is 4500, while the sum is 28.

The spelling of 21021533155 in words is "twenty-one billion, twenty-one million, five hundred thirty-three thousand, one hundred fifty-five".