661232218 has 8 divisors (see below), whose sum is σ = 995999040. Its totient is φ = 329232540.

The previous prime is 661232207. The next prime is 661232227. The reversal of 661232218 is 812232166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×661232218² = 874456092242399048, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 661232218.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 691188 + ... + 692143.

It is an arithmetic number, because the mean of its divisors is an integer number (124499880).

Almost surely, 2^661232218 is an apocalyptic number.

661232218 is a deficient number, since it is larger than the sum of its proper divisors (334766822).

661232218 is a wasteful number, since it uses less digits than its factorization.

661232218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1383572.

The product of its digits is 6912, while the sum is 31.

The square root of 661232218 is about 25714.4359844816. The cubic root of 661232218 is about 871.2002713572.

The spelling of 661232218 in words is "six hundred sixty-one million, two hundred thirty-two thousand, two hundred eighteen".