21550386375 has 96 divisors (see below), whose sum is σ = 45598460544. Its totient is φ = 9585216000.

The previous prime is 21550386349. The next prime is 21550386419. The reversal of 21550386375 is 57368305512.

21550386375 is a `hidden beast` number, since 2 + 1 + 5 + 5 + 0 + 3 + 8 + 637 + 5 = 666.

It is not a de Polignac number, because 21550386375 - 2¹² = 21550382279 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21550386375.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 254395 + ... + 328355.

It is an arithmetic number, because the mean of its divisors is an integer number (474983964).

Almost surely, 2^21550386375 is an apocalyptic number.

21550386375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21550386375 is an abundant number, since it is smaller than the sum of its proper divisors (24048074169).

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

21550386375 is a wasteful number, since it uses less digits than its factorization.

21550386375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74026 (or 74013 counting only the distinct ones).

The product of its (nonzero) digits is 756000, while the sum is 45.

The spelling of 21550386375 in words is "twenty-one billion, five hundred fifty million, three hundred eighty-six thousand, three hundred seventy-five".