291907661 has 4 divisors (see below), whose sum is σ = 291954012. Its totient is φ = 291861312.

The previous prime is 291907657. The next prime is 291907667. The reversal of 291907661 is 166709192.

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 177289225 + 114618436 = 13315^2 + 10706^2 .

It is a cyclic number.

It is not a de Polignac number, because 291907661 - 2² = 291907657 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 (291907667) 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, 11900 + ... + 26933.

It is an arithmetic number, because the mean of its divisors is an integer number (72988503).

Almost surely, 2^291907661 is an apocalyptic number.

It is an amenable number.

291907661 is a deficient number, since it is larger than the sum of its proper divisors (46351).

291907661 is an equidigital number, since it uses as much as digits as its factorization.

291907661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46350.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 291907661 is about 17085.3054113762. The cubic root of 291907661 is about 663.3588044112.

The spelling of 291907661 in words is "two hundred ninety-one million, nine hundred seven thousand, six hundred sixty-one".