15561995 has 4 divisors (see below), whose sum is σ = 18674400. Its totient is φ = 12449592.

The previous prime is 15561991. The next prime is 15562013. The reversal of 15561995 is 59916551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 59916551 = 17 ⋅3524503.

It is a cyclic number.

It is not a de Polignac number, because 15561995 - 2² = 15561991 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15561991) 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, 1556195 + ... + 1556204.

It is an arithmetic number, because the mean of its divisors is an integer number (4668600).

Almost surely, 2^15561995 is an apocalyptic number.

15561995 is a deficient number, since it is larger than the sum of its proper divisors (3112405).

15561995 is an equidigital number, since it uses as much as digits as its factorization.

15561995 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3112404.

The product of its digits is 60750, while the sum is 41.

The square root of 15561995 is about 3944.8694528463. The cubic root of 15561995 is about 249.6635206631.

The spelling of 15561995 in words is "fifteen million, five hundred sixty-one thousand, nine hundred ninety-five".