15230721 has 16 divisors (see below), whose sum is σ = 22696128. Its totient is φ = 9004800.

The previous prime is 15230711. The next prime is 15230731. The reversal of 15230721 is 12703251.

It is an interprime number because it is at equal distance from previous prime (15230711) and next prime (15230731).

It is not a de Polignac number, because 15230721 - 2¹¹ = 15228673 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (15230711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4276 + ... + 6981.

It is an arithmetic number, because the mean of its divisors is an integer number (1418508).

Almost surely, 2^15230721 is an apocalyptic number.

15230721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15230721 is a deficient number, since it is larger than the sum of its proper divisors (7465407).

15230721 is a wasteful number, since it uses less digits than its factorization.

15230721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11312.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 15230721 is about 3902.6556343085. The cubic root of 15230721 is about 247.8792390297.

Adding to 15230721 its reverse (12703251), we get a palindrome (27933972).

It can be divided in two parts, 15230 and 721, that added together give a palindrome (15951).

The spelling of 15230721 in words is "fifteen million, two hundred thirty thousand, seven hundred twenty-one".