491251801 has 2 divisors, whose sum is σ = 491251802. Its totient is φ = 491251800.

The previous prime is 491251781. The next prime is 491251819. The reversal of 491251801 is 108152194.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 489073225 + 2178576 = 22115^2 + 1476^2 .

It is a cyclic number.

It is not a de Polignac number, because 491251801 - 2¹⁵ = 491219033 is a prime.

It is not a weakly prime, because it can be changed into another prime (491251861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245625900 + 245625901.

It is an arithmetic number, because the mean of its divisors is an integer number (245625901).

Almost surely, 2^491251801 is an apocalyptic number.

It is an amenable number.

491251801 is a deficient number, since it is larger than the sum of its proper divisors (1).

491251801 is an equidigital number, since it uses as much as digits as its factorization.

491251801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 491251801 is about 22164.2008879183. The cubic root of 491251801 is about 789.0442969556.

The spelling of 491251801 in words is "four hundred ninety-one million, two hundred fifty-one thousand, eight hundred one".