15221918 has 16 divisors (see below), whose sum is σ = 23432976. Its totient is φ = 7413120.

The previous prime is 15221917. The next prime is 15221963. The reversal of 15221918 is 81912251.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15221917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16838 + ... + 17718.

It is an arithmetic number, because the mean of its divisors is an integer number (1464561).

Almost surely, 2^15221918 is an apocalyptic number.

15221918 is a deficient number, since it is larger than the sum of its proper divisors (8211058).

15221918 is a wasteful number, since it uses less digits than its factorization.

15221918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1099.

The product of its digits is 1440, while the sum is 29.

The square root of 15221918 is about 3901.5276495240. The cubic root of 15221918 is about 247.8314736947.

The spelling of 15221918 in words is "fifteen million, two hundred twenty-one thousand, nine hundred eighteen".