21575256424 has 8 divisors (see below), whose sum is σ = 40453605810. Its totient is φ = 10787628208.

The previous prime is 21575256419. The next prime is 21575256463. The reversal of 21575256424 is 42465257512.

It can be written as a sum of positive squares in only one way, i.e., 13199712100 + 8375544324 = 114890^2 + 91518^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21575256424² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1348453519 + ... + 1348453534.

Almost surely, 2^21575256424 is an apocalyptic number.

It is an amenable number.

21575256424 is a deficient number, since it is larger than the sum of its proper divisors (18878349386).

21575256424 is a wasteful number, since it uses less digits than its factorization.

21575256424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2696907059 (or 2696907055 counting only the distinct ones).

The product of its digits is 672000, while the sum is 43.

The spelling of 21575256424 in words is "twenty-one billion, five hundred seventy-five million, two hundred fifty-six thousand, four hundred twenty-four".