643525137 has 12 divisors (see below), whose sum is σ = 931369140. Its totient is φ = 428170848.

The previous prime is 643525121. The next prime is 643525139. The reversal of 643525137 is 731525346.

643525137 is a `hidden beast` number, since 643 + 5 + 2 + 5 + 1 + 3 + 7 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 267126336 + 376398801 = 16344^2 + 19401^2 .

It is not a de Polignac number, because 643525137 - 2⁴ = 643525121 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643525139) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 65658 + ... + 74819.

It is an arithmetic number, because the mean of its divisors is an integer number (77614095).

Almost surely, 2^643525137 is an apocalyptic number.

It is an amenable number.

643525137 is a deficient number, since it is larger than the sum of its proper divisors (287844003).

643525137 is a wasteful number, since it uses less digits than its factorization.

643525137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140992 (or 140989 counting only the distinct ones).

The product of its digits is 75600, while the sum is 36.

The square root of 643525137 is about 25367.7972437498. The cubic root of 643525137 is about 863.3532043580.

The spelling of 643525137 in words is "six hundred forty-three million, five hundred twenty-five thousand, one hundred thirty-seven".