661660212 has 24 divisors (see below), whose sum is σ = 1545695200. Its totient is φ = 220293216.

The previous prime is 661660177. The next prime is 661660217. The reversal of 661660212 is 212066166.

It is a super-2 number, since 2×661660212² = 875588472287769888, 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 661660212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661660217) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21787 + ... + 42402.

Almost surely, 2^661660212 is an apocalyptic number.

It is an amenable number.

661660212 is an abundant number, since it is smaller than the sum of its proper divisors (884034988).

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

661660212 is a wasteful number, since it uses less digits than its factorization.

661660212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65055 (or 65053 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 661660212 is about 25722.7566951911. The cubic root of 661660212 is about 871.3881973027.

The spelling of 661660212 in words is "six hundred sixty-one million, six hundred sixty thousand, two hundred twelve".