15890981 has 2 divisors, whose sum is σ = 15890982. Its totient is φ = 15890980.

The previous prime is 15890977. The next prime is 15890983. The reversal of 15890981 is 18909851.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14025025 + 1865956 = 3745^2 + 1366^2 .

It is an emirp because it is prime and its reverse (18909851) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15890981 - 2² = 15890977 is a prime.

It is a super-2 number, since 2×15890981² = 505046554284722, which contains 22 as substring.

Together with 15890983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15890983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7945490 + 7945491.

It is an arithmetic number, because the mean of its divisors is an integer number (7945491).

Almost surely, 2^15890981 is an apocalyptic number.

It is an amenable number.

15890981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15890981 is an equidigital number, since it uses as much as digits as its factorization.

15890981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 41.

The square root of 15890981 is about 3986.3493324093. The cubic root of 15890981 is about 251.4105912928.

The spelling of 15890981 in words is "fifteen million, eight hundred ninety thousand, nine hundred eighty-one".