642404220426 has 48 divisors (see below), whose sum is σ = 1405880335080. Its totient is φ = 211980873600.

The previous prime is 642404220421. The next prime is 642404220433. The reversal of 642404220426 is 624022404246.

642404220426 is a `hidden beast` number, since 6 + 4 + 2 + 4 + 0 + 4 + 220 + 426 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 584972577225 + 57431643201 = 764835^2 + 239649^2 .

It is a super-2 number, since 2×642404220426² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (642404220421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13088740 + ... + 13137728.

Almost surely, 2^642404220426 is an apocalyptic number.

642404220426 is an abundant number, since it is smaller than the sum of its proper divisors (763476114654).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642404220426 is a wasteful number, since it uses less digits than its factorization.

642404220426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56311 (or 56308 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 36.

The spelling of 642404220426 in words is "six hundred forty-two billion, four hundred four million, two hundred twenty thousand, four hundred twenty-six".