15397981 has 2 divisors, whose sum is σ = 15397982. Its totient is φ = 15397980.

The previous prime is 15397973. The next prime is 15398011. The reversal of 15397981 is 18979351.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15327225 + 70756 = 3915^2 + 266^2 .

It is a cyclic number.

It is not a de Polignac number, because 15397981 - 2³ = 15397973 is a prime.

It is a super-2 number, since 2×15397981² = 474195637752722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15397951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7698990 + 7698991.

It is an arithmetic number, because the mean of its divisors is an integer number (7698991).

Almost surely, 2^15397981 is an apocalyptic number.

It is an amenable number.

15397981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15397981 is an equidigital number, since it uses as much as digits as its factorization.

15397981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68040, while the sum is 43.

The square root of 15397981 is about 3924.0261212178. The cubic root of 15397981 is about 248.7833203684.

The spelling of 15397981 in words is "fifteen million, three hundred ninety-seven thousand, nine hundred eighty-one".