21351431663475 has 12 divisors (see below), whose sum is σ = 35301033683736. Its totient is φ = 11387430220480.

The previous prime is 21351431663461. The next prime is 21351431663477. The reversal of 21351431663475 is 57436613415312.

It is not a de Polignac number, because 21351431663475 - 2⁴ = 21351431663459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21351431663477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 142342877682 + ... + 142342877831.

It is an arithmetic number, because the mean of its divisors is an integer number (2941752806978).

Almost surely, 2^{21351431663475} is an apocalyptic number.

21351431663475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21351431663475 is a deficient number, since it is larger than the sum of its proper divisors (13949602020261).

21351431663475 is a wasteful number, since it uses less digits than its factorization.

21351431663475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284685755526 (or 284685755521 counting only the distinct ones).

The product of its digits is 5443200, while the sum is 51.

The spelling of 21351431663475 in words is "twenty-one trillion, three hundred fifty-one billion, four hundred thirty-one million, six hundred sixty-three thousand, four hundred seventy-five".