15909989 has 2 divisors, whose sum is σ = 15909990. Its totient is φ = 15909988.

The previous prime is 15909961. The next prime is 15910001. The reversal of 15909989 is 98990951.

15909989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12040900 + 3869089 = 3470^2 + 1967^2 .

It is an emirp because it is prime and its reverse (98990951) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15909989 is a prime.

It is a super-3 number, since 3×15909989³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15909919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7954994 + 7954995.

It is an arithmetic number, because the mean of its divisors is an integer number (7954995).

Almost surely, 2^15909989 is an apocalyptic number.

It is an amenable number.

15909989 is a deficient number, since it is larger than the sum of its proper divisors (1).

15909989 is an equidigital number, since it uses as much as digits as its factorization.

15909989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 262440, while the sum is 50.

The square root of 15909989 is about 3988.7327561520. The cubic root of 15909989 is about 251.5107929605.

The spelling of 15909989 in words is "fifteen million, nine hundred nine thousand, nine hundred eighty-nine".