666521432 has 8 divisors (see below), whose sum is σ = 1249727700. Its totient is φ = 333260712.

The previous prime is 666521423. The next prime is 666521437. The reversal of 666521432 is 234125666.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 666521392 and 666521401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666521437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41657582 + ... + 41657597.

Almost surely, 2^666521432 is an apocalyptic number.

It is an amenable number.

666521432 is a deficient number, since it is larger than the sum of its proper divisors (583206268).

666521432 is a wasteful number, since it uses less digits than its factorization.

666521432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83315185 (or 83315181 counting only the distinct ones).

The product of its digits is 51840, while the sum is 35.

The square root of 666521432 is about 25817.0763642981. The cubic root of 666521432 is about 873.5170230453.

The spelling of 666521432 in words is "six hundred sixty-six million, five hundred twenty-one thousand, four hundred thirty-two".