15608981 has 4 divisors (see below), whose sum is σ = 15873600. Its totient is φ = 15344364.

The previous prime is 15608969. The next prime is 15608993. The reversal of 15608981 is 18980651.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18980651 = 641 ⋅29611.

It is an interprime number because it is at equal distance from previous prime (15608969) and next prime (15608993).

It is a cyclic number.

It is not a de Polignac number, because 15608981 - 2¹⁰ = 15607957 is a prime.

It is a super-2 number, since 2×15608981² = 487280575716722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15608911) 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 in 3 ways as a sum of consecutive naturals, for example, 132221 + ... + 132338.

It is an arithmetic number, because the mean of its divisors is an integer number (3968400).

Almost surely, 2^15608981 is an apocalyptic number.

It is an amenable number.

15608981 is a deficient number, since it is larger than the sum of its proper divisors (264619).

15608981 is an equidigital number, since it uses as much as digits as its factorization.

15608981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264618.

The product of its (nonzero) digits is 17280, while the sum is 38.

The square root of 15608981 is about 3950.8202945717. The cubic root of 15608981 is about 249.9145361204.

The spelling of 15608981 in words is "fifteen million, six hundred eight thousand, nine hundred eighty-one".