15399997 has 2 divisors, whose sum is σ = 15399998. Its totient is φ = 15399996.

The previous prime is 15399983. The next prime is 15400031. The reversal of 15399997 is 79999351.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15280281 + 119716 = 3909^2 + 346^2 .

It is a cyclic number.

It is not a de Polignac number, because 15399997 - 2⁷ = 15399869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15399947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7699998 + 7699999.

It is an arithmetic number, because the mean of its divisors is an integer number (7699999).

Almost surely, 2^15399997 is an apocalyptic number.

It is an amenable number.

15399997 is a deficient number, since it is larger than the sum of its proper divisors (1).

15399997 is an equidigital number, since it uses as much as digits as its factorization.

15399997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 688905, while the sum is 52.

The square root of 15399997 is about 3924.2829918343. The cubic root of 15399997 is about 248.7941773174.

The spelling of 15399997 in words is "fifteen million, three hundred ninety-nine thousand, nine hundred ninety-seven".