661173012 has 18 divisors (see below), whose sum is σ = 1671298538. Its totient is φ = 220390992.

The previous prime is 661172999. The next prime is 661173043. The reversal of 661173012 is 210371166.

661173012 is a `hidden beast` number, since 6 + 611 + 7 + 30 + 12 = 666.

It can be written as a sum of positive squares in only one way, i.e., 363817476 + 297355536 = 19074^2 + 17244^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9182923 + ... + 9182994.

Almost surely, 2^661173012 is an apocalyptic number.

It is an amenable number.

661173012 is an abundant number, since it is smaller than the sum of its proper divisors (1010125526).

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

661173012 is a wasteful number, since it uses less digits than its factorization.

661173012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18365927 (or 18365922 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 661173012 is about 25713.2847376604. The cubic root of 661173012 is about 871.1742684789.

The spelling of 661173012 in words is "six hundred sixty-one million, one hundred seventy-three thousand, twelve".