15381921 has 8 divisors (see below), whose sum is σ = 21170944. Its totient is φ = 9923760.

The previous prime is 15381913. The next prime is 15381967. The reversal of 15381921 is 12918351.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 15381921 - 2³ = 15381913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15381911) 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 7 ways as a sum of consecutive naturals, for example, 82606 + ... + 82791.

It is an arithmetic number, because the mean of its divisors is an integer number (2646368).

Almost surely, 2^15381921 is an apocalyptic number.

It is an amenable number.

15381921 is a deficient number, since it is larger than the sum of its proper divisors (5789023).

15381921 is a wasteful number, since it uses less digits than its factorization.

15381921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165431.

The product of its digits is 2160, while the sum is 30.

The square root of 15381921 is about 3921.9792197308. The cubic root of 15381921 is about 248.6967971198.

The spelling of 15381921 in words is "fifteen million, three hundred eighty-one thousand, nine hundred twenty-one".