15172720 has 40 divisors (see below), whose sum is σ = 35689680. Its totient is φ = 5998080.

The previous prime is 15172711. The next prime is 15172723. The reversal of 15172720 is 2727151.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×15172720² = 460422864396800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15172723) 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, 6055 + ... + 8185.

It is an arithmetic number, because the mean of its divisors is an integer number (892242).

Almost surely, 2^15172720 is an apocalyptic number.

15172720 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 15172720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17844840).

15172720 is an abundant number, since it is smaller than the sum of its proper divisors (20516960).

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

15172720 is a wasteful number, since it uses less digits than its factorization.

15172720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2233 (or 2227 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 15172720 is about 3895.2175805724. The cubic root of 15172720 is about 247.5641842855.

Adding to 15172720 its reverse (2727151), we get a palindrome (17899871).

The spelling of 15172720 in words is "fifteen million, one hundred seventy-two thousand, seven hundred twenty".