15072721 has 8 divisors (see below), whose sum is σ = 15679080. Its totient is φ = 14472192.

The previous prime is 15072713. The next prime is 15072737. The reversal of 15072721 is 12727051.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 746496 + 14326225 = 864^2 + 3785^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 15072721 - 2³ = 15072713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15082721) 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, 4251 + ... + 6943.

It is an arithmetic number, because the mean of its divisors is an integer number (1959885).

Almost surely, 2^15072721 is an apocalyptic number.

It is an amenable number.

15072721 is a deficient number, since it is larger than the sum of its proper divisors (606359).

15072721 is a wasteful number, since it uses less digits than its factorization.

15072721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2915.

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

The square root of 15072721 is about 3882.3602357329. The cubic root of 15072721 is about 247.0191104557.

Adding to 15072721 its reverse (12727051), we get a palindrome (27799772).

The spelling of 15072721 in words is "fifteen million, seventy-two thousand, seven hundred twenty-one".