15623989 has 2 divisors, whose sum is σ = 15623990. Its totient is φ = 15623988.

The previous prime is 15623981. The next prime is 15624001. The reversal of 15623989 is 98932651.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13616100 + 2007889 = 3690^2 + 1417^2 .

It is a cyclic number.

It is not a de Polignac number, because 15623989 - 2³ = 15623981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15623981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7811994 + 7811995.

It is an arithmetic number, because the mean of its divisors is an integer number (7811995).

Almost surely, 2^15623989 is an apocalyptic number.

It is an amenable number.

15623989 is a deficient number, since it is larger than the sum of its proper divisors (1).

15623989 is an equidigital number, since it uses as much as digits as its factorization.

15623989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 43.

The square root of 15623989 is about 3952.7191906332. The cubic root of 15623989 is about 249.9946078837.

The spelling of 15623989 in words is "fifteen million, six hundred twenty-three thousand, nine hundred eighty-nine".