491021281 has 3 divisors (see below), whose sum is σ = 491043441. Its totient is φ = 490999122.

The previous prime is 491021239. The next prime is 491021317. The reversal of 491021281 is 182120194.

The square root of 491021281 is 22159.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 491021281 - 2¹⁵ = 490988513 is a prime.

It is a super-2 number, since 2×491021281² = 482203796789761922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491021231) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 11080 + ... + 33238.

It is an arithmetic number, because the mean of its divisors is an integer number (163681147).

Almost surely, 2^491021281 is an apocalyptic number.

491021281 is the 22159-th square number.

491021281 is the 11080-th centered octagonal number.

It is an amenable number.

491021281 is a deficient number, since it is larger than the sum of its proper divisors (22160).

491021281 is an frugal number, since it uses more digits than its factorization.

491021281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44318 (or 22159 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 28.

The cubic root of 491021281 is about 788.9208579174.

The spelling of 491021281 in words is "four hundred ninety-one million, twenty-one thousand, two hundred eighty-one".