661180836 has 12 divisors (see below), whose sum is σ = 1542755312. Its totient is φ = 220393608.

The previous prime is 661180823. The next prime is 661180837. The reversal of 661180836 is 638081166.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 661180794 and 661180803.

It is not an unprimeable number, because it can be changed into a prime (661180837) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27549190 + ... + 27549213.

Almost surely, 2^661180836 is an apocalyptic number.

It is an amenable number.

661180836 is an abundant number, since it is smaller than the sum of its proper divisors (881574476).

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

661180836 is a wasteful number, since it uses less digits than its factorization.

661180836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55098410 (or 55098408 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 661180836 is about 25713.4368764660. The cubic root of 661180836 is about 871.1777048162.

The spelling of 661180836 in words is "six hundred sixty-one million, one hundred eighty thousand, eight hundred thirty-six".