15117921 has 60 divisors (see below), whose sum is σ = 28388052. Its totient is φ = 7947072.

The previous prime is 15117919. The next prime is 15117937. The reversal of 15117921 is 12971151.

It can be written as a sum of positive squares in 2 ways, for example, as 8767521 + 6350400 = 2961^2 + 2520^2 .

It is not a de Polignac number, because 15117921 - 2¹ = 15117919 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (15117721) 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 59 ways as a sum of consecutive naturals, for example, 51451 + ... + 51743.

Almost surely, 2^15117921 is an apocalyptic number.

It is an amenable number.

15117921 is a deficient number, since it is larger than the sum of its proper divisors (13270131).

15117921 is a wasteful number, since it uses less digits than its factorization.

15117921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332 (or 316 counting only the distinct ones).

The product of its digits is 630, while the sum is 27.

The square root of 15117921 is about 3888.1770793008. The cubic root of 15117921 is about 247.2657839344.

The spelling of 15117921 in words is "fifteen million, one hundred seventeen thousand, nine hundred twenty-one".