15691481 has 6 divisors (see below), whose sum is σ = 16991550. Its totient is φ = 14484288.

The previous prime is 15691477. The next prime is 15691483. The reversal of 15691481 is 18419651.

It can be written as a sum of positive squares in 3 ways, for example, as 160000 + 15531481 = 400^2 + 3941^2 .

It is not a de Polignac number, because 15691481 - 2² = 15691477 is a prime.

It is a super-2 number, since 2×15691481² = 492445151946722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (15691483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 46256 + ... + 46593.

It is an arithmetic number, because the mean of its divisors is an integer number (2831925).

Almost surely, 2^15691481 is an apocalyptic number.

It is an amenable number.

15691481 is a deficient number, since it is larger than the sum of its proper divisors (1300069).

15691481 is an equidigital number, since it uses as much as digits as its factorization.

15691481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92875 (or 92862 counting only the distinct ones).

The product of its digits is 8640, while the sum is 35.

The square root of 15691481 is about 3961.2474045432. The cubic root of 15691481 is about 250.3540636523.

The spelling of 15691481 in words is "fifteen million, six hundred ninety-one thousand, four hundred eighty-one".