15291981 has 6 divisors (see below), whose sum is σ = 22088430. Its totient is φ = 10194648.

The previous prime is 15291973. The next prime is 15292007. The reversal of 15291981 is 18919251.

It can be written as a sum of positive squares in only one way, i.e., 15139881 + 152100 = 3891^2 + 390^2 .

It is not a de Polignac number, because 15291981 - 2³ = 15291973 is a prime.

It is a super-2 number, since 2×15291981² = 467689365808722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15291911) 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 5 ways as a sum of consecutive naturals, for example, 849546 + ... + 849563.

It is an arithmetic number, because the mean of its divisors is an integer number (3681405).

Almost surely, 2^15291981 is an apocalyptic number.

It is an amenable number.

15291981 is a deficient number, since it is larger than the sum of its proper divisors (6796449).

15291981 is a wasteful number, since it uses less digits than its factorization.

15291981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1699115 (or 1699112 counting only the distinct ones).

The product of its digits is 6480, while the sum is 36.

The square root of 15291981 is about 3910.4962600673. The cubic root of 15291981 is about 248.2111289589.

The spelling of 15291981 in words is "fifteen million, two hundred ninety-one thousand, nine hundred eighty-one".