561021961 has 2 divisors, whose sum is σ = 561021962. Its totient is φ = 561021960.

The previous prime is 561021953. The next prime is 561022027. The reversal of 561021961 is 169120165.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 557196025 + 3825936 = 23605^2 + 1956^2 .

It is a cyclic number.

It is not a de Polignac number, because 561021961 - 2³ = 561021953 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (561025961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280510980 + 280510981.

It is an arithmetic number, because the mean of its divisors is an integer number (280510981).

Almost surely, 2^561021961 is an apocalyptic number.

It is an amenable number.

561021961 is a deficient number, since it is larger than the sum of its proper divisors (1).

561021961 is an equidigital number, since it uses as much as digits as its factorization.

561021961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 561021961 is about 23685.9021571905. The cubic root of 561021961 is about 824.7581591718.

The spelling of 561021961 in words is "five hundred sixty-one million, twenty-one thousand, nine hundred sixty-one".