661172499 has 48 divisors (see below), whose sum is σ = 1063902112. Its totient is φ = 393030144.

The previous prime is 661172489. The next prime is 661172503. The reversal of 661172499 is 994271166.

661172499 is a `hidden beast` number, since 6 + 611 + 7 + 24 + 9 + 9 = 666.

It is not a de Polignac number, because 661172499 - 2²³ = 652783891 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661172419) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 705159 + ... + 706095.

Almost surely, 2^661172499 is an apocalyptic number.

661172499 is a deficient number, since it is larger than the sum of its proper divisors (402729613).

661172499 is a wasteful number, since it uses less digits than its factorization.

661172499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156 (or 1153 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 661172499 is about 25713.2747622702. The cubic root of 661172499 is about 871.1740431659.

The spelling of 661172499 in words is "six hundred sixty-one million, one hundred seventy-two thousand, four hundred ninety-nine".