15221864 has 32 divisors (see below), whose sum is σ = 33113280. Its totient is φ = 6424704.

The previous prime is 15221863. The next prime is 15221893. The reversal of 15221864 is 46812251.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15221861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1724 + ... + 5780.

It is an arithmetic number, because the mean of its divisors is an integer number (1034790).

Almost surely, 2^15221864 is an apocalyptic number.

15221864 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15221864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16556640).

15221864 is an abundant number, since it is smaller than the sum of its proper divisors (17891416).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15221864 is a wasteful number, since it uses less digits than its factorization.

15221864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4137 (or 4133 counting only the distinct ones).

The product of its digits is 3840, while the sum is 29.

The square root of 15221864 is about 3901.5207291516. The cubic root of 15221864 is about 247.8311806323.

The spelling of 15221864 in words is "fifteen million, two hundred twenty-one thousand, eight hundred sixty-four".