15220440 has 128 divisors (see below), whose sum is σ = 53784000. Its totient is φ = 3815424.

The previous prime is 15220421. The next prime is 15220441. The reversal of 15220440 is 4402251.

15220440 is a `hidden beast` number, since 1 + 5 + 220 + 440 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15220441) 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 31 ways as a sum of consecutive naturals, for example, 17946 + ... + 18774.

Almost surely, 2^15220440 is an apocalyptic number.

15220440 is a gapful number since it is divisible by the number (10) 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 15220440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26892000).

15220440 is an abundant number, since it is smaller than the sum of its proper divisors (38563560).

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

15220440 is a wasteful number, since it uses less digits than its factorization.

15220440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 866 (or 856 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 15220440 is about 3901.3382319404. The cubic root of 15220440 is about 247.8234522182.

Adding to 15220440 its reverse (4402251), we get a palindrome (19622691).

The spelling of 15220440 in words is "fifteen million, two hundred twenty thousand, four hundred forty".