684172491 has 4 divisors (see below), whose sum is σ = 912229992. Its totient is φ = 456114992.

The previous prime is 684172487. The next prime is 684172499. The reversal of 684172491 is 194271486.

684172491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 684172491 - 2² = 684172487 is a prime.

It is a super-2 number, since 2×684172491² = 936183994882290162, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (684172499) 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, 114028746 + ... + 114028751.

It is an arithmetic number, because the mean of its divisors is an integer number (228057498).

Almost surely, 2^684172491 is an apocalyptic number.

684172491 is a deficient number, since it is larger than the sum of its proper divisors (228057501).

684172491 is a wasteful number, since it uses less digits than its factorization.

684172491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228057500.

The product of its digits is 96768, while the sum is 42.

The square root of 684172491 is about 26156.6911324808. The cubic root of 684172491 is about 881.1608693719.

The spelling of 684172491 in words is "six hundred eighty-four million, one hundred seventy-two thousand, four hundred ninety-one".