15564989 has 4 divisors (see below), whose sum is σ = 16980000. Its totient is φ = 14149980.

The previous prime is 15564977. The next prime is 15565001. The reversal of 15564989 is 98946551.

It is a happy number.

15564989 is nontrivially palindromic in base 12.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (15564977) and next prime (15565001).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15564989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15564919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 707489 + ... + 707510.

It is an arithmetic number, because the mean of its divisors is an integer number (4245000).

Almost surely, 2^15564989 is an apocalyptic number.

It is an amenable number.

15564989 is a deficient number, since it is larger than the sum of its proper divisors (1415011).

15564989 is a wasteful number, since it uses less digits than its factorization.

15564989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1415010.

The product of its digits is 388800, while the sum is 47.

The square root of 15564989 is about 3945.2489148341. The cubic root of 15564989 is about 249.6795307066.

The spelling of 15564989 in words is "fifteen million, five hundred sixty-four thousand, nine hundred eighty-nine".