15872321 has 2 divisors, whose sum is σ = 15872322. Its totient is φ = 15872320.

The previous prime is 15872303. The next prime is 15872327. The reversal of 15872321 is 12327851.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8473921 + 7398400 = 2911^2 + 2720^2 .

It is a cyclic number.

It is not a de Polignac number, because 15872321 - 2⁶ = 15872257 is a prime.

It is not a weakly prime, because it can be changed into another prime (15872327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7936160 + 7936161.

It is an arithmetic number, because the mean of its divisors is an integer number (7936161).

Almost surely, 2^15872321 is an apocalyptic number.

It is an amenable number.

15872321 is a deficient number, since it is larger than the sum of its proper divisors (1).

15872321 is an equidigital number, since it uses as much as digits as its factorization.

15872321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 29.

The square root of 15872321 is about 3984.0081576222. The cubic root of 15872321 is about 251.3121463721.

The spelling of 15872321 in words is "fifteen million, eight hundred seventy-two thousand, three hundred twenty-one".