2391817621 has 2 divisors, whose sum is σ = 2391817622. Its totient is φ = 2391817620.

The previous prime is 2391817613. The next prime is 2391817699. The reversal of 2391817621 is 1267181932.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2125671025 + 266146596 = 46105^2 + 16314^2 .

It is a cyclic number.

It is not a de Polignac number, because 2391817621 - 2³ = 2391817613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2391817321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1195908810 + 1195908811.

It is an arithmetic number, because the mean of its divisors is an integer number (1195908811).

Almost surely, 2^2391817621 is an apocalyptic number.

It is an amenable number.

2391817621 is a deficient number, since it is larger than the sum of its proper divisors (1).

2391817621 is an equidigital number, since it uses as much as digits as its factorization.

2391817621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 40.

The square root of 2391817621 is about 48906.2124990272. The cubic root of 2391817621 is about 1337.3426249283.

The spelling of 2391817621 in words is "two billion, three hundred ninety-one million, eight hundred seventeen thousand, six hundred twenty-one".