561851881 has 2 divisors, whose sum is σ = 561851882. Its totient is φ = 561851880.

The previous prime is 561851863. The next prime is 561851891. The reversal of 561851881 is 188158165.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 401601600 + 160250281 = 20040^2 + 12659^2 .

It is a cyclic number.

It is not a de Polignac number, because 561851881 - 2⁷ = 561851753 is a prime.

It is a super-2 number, since 2×561851881² = 631355072366476322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (561851891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280925940 + 280925941.

It is an arithmetic number, because the mean of its divisors is an integer number (280925941).

Almost surely, 2^561851881 is an apocalyptic number.

It is an amenable number.

561851881 is a deficient number, since it is larger than the sum of its proper divisors (1).

561851881 is an equidigital number, since it uses as much as digits as its factorization.

561851881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 76800, while the sum is 43.

The square root of 561851881 is about 23703.4149649370. The cubic root of 561851881 is about 825.1646471510.

The spelling of 561851881 in words is "five hundred sixty-one million, eight hundred fifty-one thousand, eight hundred eighty-one".