561376391 has 2 divisors, whose sum is σ = 561376392. Its totient is φ = 561376390.

The previous prime is 561376379. The next prime is 561376421. The reversal of 561376391 is 193673165.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-561376391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561376301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280688195 + 280688196.

It is an arithmetic number, because the mean of its divisors is an integer number (280688196).

Almost surely, 2^561376391 is an apocalyptic number.

561376391 is a deficient number, since it is larger than the sum of its proper divisors (1).

561376391 is an equidigital number, since it uses as much as digits as its factorization.

561376391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 102060, while the sum is 41.

The square root of 561376391 is about 23693.3828526025. The cubic root of 561376391 is about 824.9318050763.

The spelling of 561376391 in words is "five hundred sixty-one million, three hundred seventy-six thousand, three hundred ninety-one".