15420440 has 32 divisors (see below), whose sum is σ = 39653280. Its totient is φ = 5286912.

The previous prime is 15420421. The next prime is 15420443. The reversal of 15420440 is 4402451.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15420443) 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, 27257 + ... + 27816.

It is an arithmetic number, because the mean of its divisors is an integer number (1239165).

Almost surely, 2^15420440 is an apocalyptic number.

15420440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15420440 is an abundant number, since it is smaller than the sum of its proper divisors (24232840).

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

15420440 is a wasteful number, since it uses less digits than its factorization.

15420440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55091 (or 55087 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 15420440 is about 3926.8868076378. The cubic root of 15420440 is about 248.9042173926.

Adding to 15420440 its reverse (4402451), we get a palindrome (19822891).

The spelling of 15420440 in words is "fifteen million, four hundred twenty thousand, four hundred forty".