643905125 has 32 divisors (see below), whose sum is σ = 867559680. Its totient is φ = 475675200.

The previous prime is 643905083. The next prime is 643905131. The reversal of 643905125 is 521509346.

It is not a de Polignac number, because 643905125 - 2¹⁸ = 643642981 is a prime.

It is a super-2 number, since 2×643905125² = 829227620002531250, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79514 + ... + 87236.

It is an arithmetic number, because the mean of its divisors is an integer number (27111240).

Almost surely, 2^643905125 is an apocalyptic number.

It is an amenable number.

643905125 is a deficient number, since it is larger than the sum of its proper divisors (223654555).

643905125 is a wasteful number, since it uses less digits than its factorization.

643905125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7790 (or 7780 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 35.

The square root of 643905125 is about 25375.2857126772. The cubic root of 643905125 is about 863.5231015323.

The spelling of 643905125 in words is "six hundred forty-three million, nine hundred five thousand, one hundred twenty-five".