21010551506 has 16 divisors (see below), whose sum is σ = 37179962880. Its totient is φ = 8714053440.

The previous prime is 21010551449. The next prime is 21010551521. The reversal of 21010551506 is 60515501012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24205271 + ... + 24206138.

It is an arithmetic number, because the mean of its divisors is an integer number (2323747680).

Almost surely, 2^21010551506 is an apocalyptic number.

21010551506 is a deficient number, since it is larger than the sum of its proper divisors (16169411374).

21010551506 is a wasteful number, since it uses less digits than its factorization.

21010551506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48411449.

The product of its (nonzero) digits is 1500, while the sum is 26.

The spelling of 21010551506 in words is "twenty-one billion, ten million, five hundred fifty-one thousand, five hundred six".