15715561 has 4 divisors (see below), whose sum is σ = 15773824. Its totient is φ = 15657300.

The previous prime is 15715537. The next prime is 15715571. The reversal of 15715561 is 16551751.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16551751 = 3449 ⋅4799.

It is a cyclic number.

It is not a de Polignac number, because 15715561 - 2⁵ = 15715529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15715501) 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, 28725 + ... + 29266.

It is an arithmetic number, because the mean of its divisors is an integer number (3943456).

Almost surely, 2^15715561 is an apocalyptic number.

It is an amenable number.

15715561 is a deficient number, since it is larger than the sum of its proper divisors (58263).

15715561 is an equidigital number, since it uses as much as digits as its factorization.

15715561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58262.

The product of its digits is 5250, while the sum is 31.

The square root of 15715561 is about 3964.2856859717. The cubic root of 15715561 is about 250.4820618680.

The spelling of 15715561 in words is "fifteen million, seven hundred fifteen thousand, five hundred sixty-one".