561616631 has 2 divisors, whose sum is σ = 561616632. Its totient is φ = 561616630.

The previous prime is 561616619. The next prime is 561616721. The reversal of 561616631 is 136616165.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-561616631 is a prime.

It is a super-2 number, since 2×561616631² = 630826480431580322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 561616591 and 561616600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561616331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280808315 + 280808316.

It is an arithmetic number, because the mean of its divisors is an integer number (280808316).

Almost surely, 2^561616631 is an apocalyptic number.

561616631 is a deficient number, since it is larger than the sum of its proper divisors (1).

561616631 is an equidigital number, since it uses as much as digits as its factorization.

561616631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 35.

The square root of 561616631 is about 23698.4520802520. The cubic root of 561616631 is about 825.0494643131.

The spelling of 561616631 in words is "five hundred sixty-one million, six hundred sixteen thousand, six hundred thirty-one".