661218504 has 32 divisors (see below), whose sum is σ = 1672967520. Its totient is φ = 217750016.

The previous prime is 661218497. The next prime is 661218533. The reversal of 661218504 is 405812166.

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, 163977 + ... + 167960.

It is an arithmetic number, because the mean of its divisors is an integer number (52280235).

Almost surely, 2^661218504 is an apocalyptic number.

It is an amenable number.

661218504 is an abundant number, since it is smaller than the sum of its proper divisors (1011749016).

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

661218504 is a wasteful number, since it uses less digits than its factorization.

661218504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332029 (or 332025 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 661218504 is about 25714.1693235461. The cubic root of 661218504 is about 871.1942483985.

The spelling of 661218504 in words is "six hundred sixty-one million, two hundred eighteen thousand, five hundred four".