2391994043261 has 2 divisors, whose sum is σ = 2391994043262. Its totient is φ = 2391994043260.

The previous prime is 2391994043071. The next prime is 2391994043267. The reversal of 2391994043261 is 1623404991932.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1842483179161 + 549510864100 = 1357381^2 + 741290^2 .

It is a cyclic number.

It is not a de Polignac number, because 2391994043261 - 2³⁴ = 2374814174077 is a prime.

It is a super-2 number, since 2×2391994043261² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2391994043267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1195997021630 + 1195997021631.

It is an arithmetic number, because the mean of its divisors is an integer number (1195997021631).

Almost surely, 2^{2391994043261} is an apocalyptic number.

It is an amenable number.

2391994043261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2391994043261 is an equidigital number, since it uses as much as digits as its factorization.

2391994043261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2519424, while the sum is 53.

The spelling of 2391994043261 in words is "two trillion, three hundred ninety-one billion, nine hundred ninety-four million, forty-three thousand, two hundred sixty-one".