291009481 has 9 divisors (see below), whose sum is σ = 338660199. Its totient is φ = 249334344.

The previous prime is 291009473. The next prime is 291009497. The reversal of 291009481 is 184900192.

The square root of 291009481 is 17059.

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

It can be written as a sum of positive squares in only one way, i.e., 274068025 + 16941456 = 16555^2 + 4116^2 .

It is not a de Polignac number, because 291009481 - 2³ = 291009473 is a prime.

It is a super-2 number, since 2×291009481² = 169373036063778722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (291009781) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 118195 + ... + 120631.

It is an arithmetic number, because the mean of its divisors is an integer number (37628911).

Almost surely, 2^291009481 is an apocalyptic number.

291009481 is the 17059-th square number.

291009481 is the 8530-th centered octagonal number.

It is an amenable number.

291009481 is a deficient number, since it is larger than the sum of its proper divisors (47650718).

291009481 is an frugal number, since it uses more digits than its factorization.

291009481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4888 (or 2444 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The cubic root of 291009481 is about 662.6777354386.

Multiplying 291009481 by its product of nonzero digits (5184), we get a square (1508593149504 = 1228248²).

The spelling of 291009481 in words is "two hundred ninety-one million, nine thousand, four hundred eighty-one".