491501691 has 6 divisors (see below), whose sum is σ = 709946900. Its totient is φ = 327667788.

The previous prime is 491501687. The next prime is 491501693. The reversal of 491501691 is 196105194.

491501691 is a `hidden beast` number, since 4 + 91 + 501 + 69 + 1 = 666.

It is not a de Polignac number, because 491501691 - 2² = 491501687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491501693) 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, 27305641 + ... + 27305658.

Almost surely, 2^491501691 is an apocalyptic number.

491501691 is a deficient number, since it is larger than the sum of its proper divisors (218445209).

491501691 is a wasteful number, since it uses less digits than its factorization.

491501691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54611305 (or 54611302 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 491501691 is about 22169.8374148301. The cubic root of 491501691 is about 789.1780646457.

The spelling of 491501691 in words is "four hundred ninety-one million, five hundred one thousand, six hundred ninety-one".