643434625 has 16 divisors (see below), whose sum is σ = 824715216. Its totient is φ = 500832000.

The previous prime is 643434619. The next prime is 643434661. The reversal of 643434625 is 526434346.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 117007489 + 526427136 = 10817^2 + 22944^2 .

It is not a de Polignac number, because 643434625 - 2⁵ = 643434593 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64936 + ... + 74185.

It is an arithmetic number, because the mean of its divisors is an integer number (51544701).

Almost surely, 2^643434625 is an apocalyptic number.

It is an amenable number.

643434625 is a deficient number, since it is larger than the sum of its proper divisors (181280591).

643434625 is a wasteful number, since it uses less digits than its factorization.

643434625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139173 (or 139163 counting only the distinct ones).

The product of its digits is 207360, while the sum is 37.

The square root of 643434625 is about 25366.0131869397. The cubic root of 643434625 is about 863.3127254994.

The spelling of 643434625 in words is "six hundred forty-three million, four hundred thirty-four thousand, six hundred twenty-five".