291521997361 has 16 divisors (see below), whose sum is σ = 350834882560. Its totient is φ = 236635713360.

The previous prime is 291521997359. The next prime is 291521997391. The reversal of 291521997361 is 163799125192.

It is a cyclic number.

It is not a de Polignac number, because 291521997361 - 2¹ = 291521997359 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (291521997331) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55071 + ... + 765556.

It is an arithmetic number, because the mean of its divisors is an integer number (21927180160).

Almost surely, 2^291521997361 is an apocalyptic number.

It is an amenable number.

291521997361 is a deficient number, since it is larger than the sum of its proper divisors (59312885199).

291521997361 is a wasteful number, since it uses less digits than its factorization.

291521997361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 823324.

The product of its digits is 1837080, while the sum is 55.

The spelling of 291521997361 in words is "two hundred ninety-one billion, five hundred twenty-one million, nine hundred ninety-seven thousand, three hundred sixty-one".