291997487 has 4 divisors (see below), whose sum is σ = 292243440. Its totient is φ = 291751536.

The previous prime is 291997483. The next prime is 291997493. The reversal of 291997487 is 784799192.

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

It is a cyclic number.

It is not a de Polignac number, because 291997487 - 2² = 291997483 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (291997483) 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, 121187 + ... + 123572.

It is an arithmetic number, because the mean of its divisors is an integer number (73060860).

Almost surely, 2^291997487 is an apocalyptic number.

291997487 is a deficient number, since it is larger than the sum of its proper divisors (245953).

291997487 is a wasteful number, since it uses less digits than its factorization.

291997487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245952.

The product of its digits is 2286144, while the sum is 56.

The square root of 291997487 is about 17087.9339593761. The cubic root of 291997487 is about 663.4268404890.

The spelling of 291997487 in words is "two hundred ninety-one million, nine hundred ninety-seven thousand, four hundred eighty-seven".