21097909375 has 24 divisors (see below), whose sum is σ = 26411059584. Its totient is φ = 16852500000.

The previous prime is 21097909367. The next prime is 21097909411. The reversal of 21097909375 is 57390979012.

It is not a de Polignac number, because 21097909375 - 2³ = 21097909367 is a prime.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2185810 + ... + 2195440.

It is an arithmetic number, because the mean of its divisors is an integer number (1100460816).

Almost surely, 2^21097909375 is an apocalyptic number.

21097909375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21097909375 is a deficient number, since it is larger than the sum of its proper divisors (5313150209).

21097909375 is an frugal number, since it uses more digits than its factorization.

21097909375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10357 (or 10337 counting only the distinct ones).

The product of its (nonzero) digits is 1071630, while the sum is 52.

The spelling of 21097909375 in words is "twenty-one billion, ninety-seven million, nine hundred nine thousand, three hundred seventy-five".