21013002555 has 32 divisors (see below), whose sum is σ = 34905902400. Its totient is φ = 10781363712.

The previous prime is 21013002547. The next prime is 21013002599. The reversal of 21013002555 is 55520031012.

It is a happy number.

It is not a de Polignac number, because 21013002555 - 2³ = 21013002547 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, 33301 + ... + 207689.

It is an arithmetic number, because the mean of its divisors is an integer number (1090809450).

Almost surely, 2^21013002555 is an apocalyptic number.

21013002555 is a deficient number, since it is larger than the sum of its proper divisors (13892899845).

21013002555 is a wasteful number, since it uses less digits than its factorization.

21013002555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174703.

The product of its (nonzero) digits is 1500, while the sum is 24.

Adding to 21013002555 its reverse (55520031012), we get a palindrome (76533033567).

The spelling of 21013002555 in words is "twenty-one billion, thirteen million, two thousand, five hundred fifty-five".