15969561 has 4 divisors (see below), whose sum is σ = 21292752. Its totient is φ = 10646372.

The previous prime is 15969559. The next prime is 15969593. The reversal of 15969561 is 16596951.

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 a cyclic number.

It is not a de Polignac number, because 15969561 - 2¹ = 15969559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15969761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2661591 + ... + 2661596.

It is an arithmetic number, because the mean of its divisors is an integer number (5323188).

Almost surely, 2^15969561 is an apocalyptic number.

It is an amenable number.

15969561 is a deficient number, since it is larger than the sum of its proper divisors (5323191).

15969561 is an equidigital number, since it uses as much as digits as its factorization.

15969561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5323190.

The product of its digits is 72900, while the sum is 42.

The square root of 15969561 is about 3996.1933136424. The cubic root of 15969561 is about 251.8243138017.

The spelling of 15969561 in words is "fifteen million, nine hundred sixty-nine thousand, five hundred sixty-one".