639920234025 has 18 divisors (see below), whose sum is σ = 1146168241790. Its totient is φ = 341290791360.

The previous prime is 639920233993. The next prime is 639920234027. The reversal of 639920234025 is 520432029936.

639920234025 is a `hidden beast` number, since 6 + 39 + 9 + 202 + 3 + 402 + 5 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 138991769856 + 500928464169 = 372816^2 + 707763^2 .

It is not a de Polignac number, because 639920234025 - 2⁵ = 639920233993 is a prime.

It is a super-2 number, since 2×639920234025² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (639920234027) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1422044740 + ... + 1422045189.

Almost surely, 2^639920234025 is an apocalyptic number.

It is an amenable number.

639920234025 is a deficient number, since it is larger than the sum of its proper divisors (506248007765).

639920234025 is a wasteful number, since it uses less digits than its factorization.

639920234025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2844089945 (or 2844089937 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 45.

The spelling of 639920234025 in words is "six hundred thirty-nine billion, nine hundred twenty million, two hundred thirty-four thousand, twenty-five".