661172796 has 18 divisors (see below), whose sum is σ = 1671297992. Its totient is φ = 220390920.

The previous prime is 661172791. The next prime is 661172819. The reversal of 661172796 is 697271166.

It is a happy number.

661172796 is a `hidden beast` number, since 6 + 611 + 7 + 27 + 9 + 6 = 666.

661172796 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661172791) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9182920 + ... + 9182991.

Almost surely, 2^661172796 is an apocalyptic number.

It is an amenable number.

661172796 is an abundant number, since it is smaller than the sum of its proper divisors (1010125196).

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

661172796 is a wasteful number, since it uses less digits than its factorization.

661172796 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18365921 (or 18365916 counting only the distinct ones).

The product of its digits is 190512, while the sum is 45.

The square root of 661172796 is about 25713.2805374966. The cubic root of 661172796 is about 871.1741736103.

The spelling of 661172796 in words is "six hundred sixty-one million, one hundred seventy-two thousand, seven hundred ninety-six".