21616220405425 has 24 divisors (see below), whose sum is σ = 26948397631896. Its totient is φ = 17200089661440.

The previous prime is 21616220405327. The next prime is 21616220405449. The reversal of 21616220405425 is 52450402261612.

It can be written as a sum of positive squares in 12 ways, for example, as 3827497047201 + 17788723358224 = 1956399^2 + 4217668^2 .

It is not a de Polignac number, because 21616220405425 - 2²⁹ = 21615683534513 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1824477 + ... + 6823573.

It is an arithmetic number, because the mean of its divisors is an integer number (1122849901329).

Almost surely, 2^{21616220405425} is an apocalyptic number.

21616220405425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21616220405425 is a deficient number, since it is larger than the sum of its proper divisors (5332177226471).

21616220405425 is a wasteful number, since it uses less digits than its factorization.

21616220405425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5000037 (or 5000032 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 40.

The spelling of 21616220405425 in words is "twenty-one trillion, six hundred sixteen billion, two hundred twenty million, four hundred five thousand, four hundred twenty-five".