21015610550 has 96 divisors (see below), whose sum is σ = 43767627264. Its totient is φ = 7442064000.

The previous prime is 21015610537. The next prime is 21015610571. The reversal of 21015610550 is 5501651012.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5452424 + ... + 5456276.

It is an arithmetic number, because the mean of its divisors is an integer number (455912784).

Almost surely, 2^21015610550 is an apocalyptic number.

21015610550 is an abundant number, since it is smaller than the sum of its proper divisors (22752016714).

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

21015610550 is a wasteful number, since it uses less digits than its factorization.

21015610550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4134 (or 4129 counting only the distinct ones).

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

The spelling of 21015610550 in words is "twenty-one billion, fifteen million, six hundred ten thousand, five hundred fifty".