21115352550 has 48 divisors (see below), whose sum is σ = 52536762432. Its totient is φ = 5612407200.

The previous prime is 21115352549. The next prime is 21115352563. The reversal of 21115352550 is 5525351112.

It is a super-2 number, since 2×21115352550² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 183216 + ... + 275315.

It is an arithmetic number, because the mean of its divisors is an integer number (1094515884).

Almost surely, 2^21115352550 is an apocalyptic number.

21115352550 is an abundant number, since it is smaller than the sum of its proper divisors (31421409882).

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

21115352550 is a wasteful number, since it uses less digits than its factorization.

21115352550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458853 (or 458848 counting only the distinct ones).

The product of its (nonzero) digits is 7500, while the sum is 30.

The spelling of 21115352550 in words is "twenty-one billion, one hundred fifteen million, three hundred fifty-two thousand, five hundred fifty".