15642881 has 2 divisors, whose sum is σ = 15642882. Its totient is φ = 15642880.

The previous prime is 15642827. The next prime is 15642883. The reversal of 15642881 is 18824651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8439025 + 7203856 = 2905^2 + 2684^2 .

It is a cyclic number.

It is not a de Polignac number, because 15642881 - 2¹⁴ = 15626497 is a prime.

It is a super-2 number, since 2×15642881² = 489399451960322, which contains 22 as substring.

Together with 15642883, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15642883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7821440 + 7821441.

It is an arithmetic number, because the mean of its divisors is an integer number (7821441).

Almost surely, 2^15642881 is an apocalyptic number.

It is an amenable number.

15642881 is a deficient number, since it is larger than the sum of its proper divisors (1).

15642881 is an equidigital number, since it uses as much as digits as its factorization.

15642881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15360, while the sum is 35.

The square root of 15642881 is about 3955.1082159658. The cubic root of 15642881 is about 250.0953289783.

The spelling of 15642881 in words is "fifteen million, six hundred forty-two thousand, eight hundred eighty-one".