21615613251010 has 16 divisors (see below), whose sum is σ = 38921722420536. Its totient is φ = 8643218951808.

The previous prime is 21615613251007. The next prime is 21615613251019. The reversal of 21615613251010 is 1015231651612.

It can be written as a sum of positive squares in 4 ways, for example, as 14515482786561 + 7100130464449 = 3809919^2 + 2664607^2 .

It is not an unprimeable number, because it can be changed into a prime (21615613251019) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 378263577 + ... + 378320716.

Almost surely, 2^{21615613251010} is an apocalyptic number.

21615613251010 is a deficient number, since it is larger than the sum of its proper divisors (17306109169526).

21615613251010 is a wasteful number, since it uses less digits than its factorization.

21615613251010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756587157.

The product of its (nonzero) digits is 10800, while the sum is 34.

The spelling of 21615613251010 in words is "twenty-one trillion, six hundred fifteen billion, six hundred thirteen million, two hundred fifty-one thousand, ten".