21215249056 has 12 divisors (see below), whose sum is σ = 41767521642. Its totient is φ = 10607624512.

The previous prime is 21215249051. The next prime is 21215249129. The reversal of 21215249056 is 65094251212.

It can be written as a sum of positive squares in only one way, i.e., 12125533456 + 9089715600 = 110116^2 + 95340^2 .

It is a super-2 number, since 2×21215249056² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21215249051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331488235 + ... + 331488298.

Almost surely, 2^21215249056 is an apocalyptic number.

It is an amenable number.

21215249056 is a deficient number, since it is larger than the sum of its proper divisors (20552272586).

21215249056 is an equidigital number, since it uses as much as digits as its factorization.

21215249056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662976543 (or 662976535 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 37.

The spelling of 21215249056 in words is "twenty-one billion, two hundred fifteen million, two hundred forty-nine thousand, fifty-six".