21394347975 has 216 divisors, whose sum is σ = 51739938432. Its totient is φ = 8206099200.

The previous prime is 21394347937. The next prime is 21394348043. The reversal of 21394347975 is 57974349312.

21394347975 is a `hidden beast` number, since 2 + 13 + 94 + 3 + 479 + 75 = 666.

It is not a de Polignac number, because 21394347975 - 2⁷ = 21394347847 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 2924272 + ... + 2931578.

It is an arithmetic number, because the mean of its divisors is an integer number (239536752).

Almost surely, 2^21394347975 is an apocalyptic number.

21394347975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21394347975 is an abundant number, since it is smaller than the sum of its proper divisors (30345590457).

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

21394347975 is a wasteful number, since it uses less digits than its factorization.

21394347975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7367 (or 7346 counting only the distinct ones).

The product of its digits is 5715360, while the sum is 54.

The spelling of 21394347975 in words is "twenty-one billion, three hundred ninety-four million, three hundred forty-seven thousand, nine hundred seventy-five".