643521354 has 16 divisors (see below), whose sum is σ = 1470906048. Its totient is φ = 183863232.

The previous prime is 643521331. The next prime is 643521371. The reversal of 643521354 is 453125346.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7660927 + ... + 7661010.

It is an arithmetic number, because the mean of its divisors is an integer number (91931628).

Almost surely, 2^643521354 is an apocalyptic number.

643521354 is an abundant number, since it is smaller than the sum of its proper divisors (827384694).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643521354 is a wasteful number, since it uses less digits than its factorization.

643521354 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15321949.

The product of its digits is 43200, while the sum is 33.

The square root of 643521354 is about 25367.7226806034. The cubic root of 643521354 is about 863.3515125974.

The spelling of 643521354 in words is "six hundred forty-three million, five hundred twenty-one thousand, three hundred fifty-four".