491009901 has 4 divisors (see below), whose sum is σ = 654679872. Its totient is φ = 327339932.

The previous prime is 491009879. The next prime is 491009927. The reversal of 491009901 is 109900194.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 491009901 - 2²⁵ = 457455469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491009941) 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, 81834981 + ... + 81834986.

It is an arithmetic number, because the mean of its divisors is an integer number (163669968).

Almost surely, 2^491009901 is an apocalyptic number.

It is an amenable number.

491009901 is a deficient number, since it is larger than the sum of its proper divisors (163669971).

491009901 is a wasteful number, since it uses less digits than its factorization.

491009901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163669970.

The product of its (nonzero) digits is 2916, while the sum is 33.

The square root of 491009901 is about 22158.7432179715. The cubic root of 491009901 is about 788.9147631451.

The spelling of 491009901 in words is "four hundred ninety-one million, nine thousand, nine hundred one".