491390161 has 4 divisors (see below), whose sum is σ = 491542324. Its totient is φ = 491238000.

The previous prime is 491390153. The next prime is 491390167. The reversal of 491390161 is 161093194.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 63107136 + 428283025 = 7944^2 + 20695^2 .

It is a cyclic number.

It is not a de Polignac number, because 491390161 - 2³ = 491390153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491390167) 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, 71130 + ... + 77731.

It is an arithmetic number, because the mean of its divisors is an integer number (122885581).

Almost surely, 2^491390161 is an apocalyptic number.

It is an amenable number.

491390161 is a deficient number, since it is larger than the sum of its proper divisors (152163).

491390161 is a wasteful number, since it uses less digits than its factorization.

491390161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152162.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 491390161 is about 22167.3219176336. The cubic root of 491390161 is about 789.1183675381.

The spelling of 491390161 in words is "four hundred ninety-one million, three hundred ninety thousand, one hundred sixty-one".