15239981 has 2 divisors, whose sum is σ = 15239982. Its totient is φ = 15239980.

The previous prime is 15239963. The next prime is 15239989. The reversal of 15239981 is 18993251.

15239981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14891881 + 348100 = 3859^2 + 590^2 .

It is an emirp because it is prime and its reverse (18993251) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15239981 - 2¹⁰ = 15238957 is a prime.

It is a super-2 number, since 2×15239981² = 464514041760722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15239989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7619990 + 7619991.

It is an arithmetic number, because the mean of its divisors is an integer number (7619991).

Almost surely, 2^15239981 is an apocalyptic number.

It is an amenable number.

15239981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15239981 is an equidigital number, since it uses as much as digits as its factorization.

15239981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 38.

The square root of 15239981 is about 3903.8418256892. The cubic root of 15239981 is about 247.9294642014.

The spelling of 15239981 in words is "fifteen million, two hundred thirty-nine thousand, nine hundred eighty-one".