521665434 has 40 divisors (see below), whose sum is σ = 1237683348. Its totient is φ = 163658880.

The previous prime is 521665429. The next prime is 521665457. The reversal of 521665434 is 434566125.

521665434 is a `hidden beast` number, since 5 + 216 + 6 + 5 + 434 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 398122209 + 123543225 = 19953^2 + 11115^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 91957 + ... + 97464.

Almost surely, 2^521665434 is an apocalyptic number.

521665434 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

521665434 is an abundant number, since it is smaller than the sum of its proper divisors (716017914).

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

521665434 is a wasteful number, since it uses less digits than its factorization.

521665434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189452 (or 189443 counting only the distinct ones).

The product of its digits is 86400, while the sum is 36.

The square root of 521665434 is about 22839.9963660242. The cubic root of 521665434 is about 805.0027308525.

It can be divided in two parts, 52166 and 5434, that added together give a square (57600 = 240²).

The spelling of 521665434 in words is "five hundred twenty-one million, six hundred sixty-five thousand, four hundred thirty-four".