561980981 has 2 divisors, whose sum is σ = 561980982. Its totient is φ = 561980980.

The previous prime is 561980971. The next prime is 561981023. The reversal of 561980981 is 189089165.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 408444100 + 153536881 = 20210^2 + 12391^2 .

It is a cyclic number.

It is not a de Polignac number, because 561980981 - 2¹⁸ = 561718837 is a prime.

It is a super-2 number, since 2×561980981² = 631645246011444722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561980941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280990490 + 280990491.

It is an arithmetic number, because the mean of its divisors is an integer number (280990491).

Almost surely, 2^561980981 is an apocalyptic number.

It is an amenable number.

561980981 is a deficient number, since it is larger than the sum of its proper divisors (1).

561980981 is an equidigital number, since it uses as much as digits as its factorization.

561980981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 47.

The square root of 561980981 is about 23706.1380448187. The cubic root of 561980981 is about 825.2278432835.

The spelling of 561980981 in words is "five hundred sixty-one million, nine hundred eighty thousand, nine hundred eighty-one".