21531242975 has 48 divisors (see below), whose sum is σ = 30258825216. Its totient is φ = 15056496000.

The previous prime is 21531242959. The next prime is 21531242981. The reversal of 21531242975 is 57924213512.

It is a happy number.

It is not a de Polignac number, because 21531242975 - 2⁴ = 21531242959 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 (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1330382 + ... + 1346468.

It is an arithmetic number, because the mean of its divisors is an integer number (630392192).

Almost surely, 2^21531242975 is an apocalyptic number.

21531242975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21531242975 is a deficient number, since it is larger than the sum of its proper divisors (8727582241).

21531242975 is a wasteful number, since it uses less digits than its factorization.

21531242975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16296 (or 16291 counting only the distinct ones).

The product of its digits is 151200, while the sum is 41.

The spelling of 21531242975 in words is "twenty-one billion, five hundred thirty-one million, two hundred forty-two thousand, nine hundred seventy-five".