639837025 has 9 divisors (see below), whose sum is σ = 793554771. Its totient is φ = 511768440.

The previous prime is 639837001. The next prime is 639837047. The reversal of 639837025 is 520738936.

The square root of 639837025 is 25295.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 230341329 + 409495696 = 15177^2 + 20236^2 .

It is not a de Polignac number, because 639837025 - 2⁹ = 639836513 is a prime.

It is a super-3 number, since 3×639837025³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 123946 + ... + 129004.

Almost surely, 2^639837025 is an apocalyptic number.

639837025 is the 25295-th square number.

639837025 is the 12648-th centered octagonal number.

It is an amenable number.

639837025 is a deficient number, since it is larger than the sum of its proper divisors (153717746).

639837025 is an frugal number, since it uses more digits than its factorization.

639837025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10128 (or 5064 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 43.

The cubic root of 639837025 is about 861.7007200124.

The spelling of 639837025 in words is "six hundred thirty-nine million, eight hundred thirty-seven thousand, twenty-five".