561838391 has 2 divisors, whose sum is σ = 561838392. Its totient is φ = 561838390.

The previous prime is 561838369. The next prime is 561838439. The reversal of 561838391 is 193838165.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-561838391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561838091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280919195 + 280919196.

It is an arithmetic number, because the mean of its divisors is an integer number (280919196).

Almost surely, 2^561838391 is an apocalyptic number.

561838391 is a deficient number, since it is larger than the sum of its proper divisors (1).

561838391 is an equidigital number, since it uses as much as digits as its factorization.

561838391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 44.

The square root of 561838391 is about 23703.1304050752. The cubic root of 561838391 is about 825.1580430616.

The spelling of 561838391 in words is "five hundred sixty-one million, eight hundred thirty-eight thousand, three hundred ninety-one".