642560881 has 2 divisors, whose sum is σ = 642560882. Its totient is φ = 642560880.

The previous prime is 642560879. The next prime is 642560899. The reversal of 642560881 is 188065246.

642560881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 511664400 + 130896481 = 22620^2 + 11441^2 .

It is a cyclic number.

It is not a de Polignac number, because 642560881 - 2¹ = 642560879 is a prime.

It is a super-2 number, since 2×642560881² = 825768971582992322, which contains 22 as substring.

Together with 642560879, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (642530881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321280440 + 321280441.

It is an arithmetic number, because the mean of its divisors is an integer number (321280441).

Almost surely, 2^642560881 is an apocalyptic number.

It is an amenable number.

642560881 is a deficient number, since it is larger than the sum of its proper divisors (1).

642560881 is an equidigital number, since it uses as much as digits as its factorization.

642560881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 642560881 is about 25348.7846059727. The cubic root of 642560881 is about 862.9217735779.

The spelling of 642560881 in words is "six hundred forty-two million, five hundred sixty thousand, eight hundred eighty-one".