15661005051 has 4 divisors (see below), whose sum is σ = 20881340072. Its totient is φ = 10440670032.

The previous prime is 15661005023. The next prime is 15661005071. The reversal of 15661005051 is 15050016651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15050016651 = 3 ⋅5016672217.

It is not a de Polignac number, because 15661005051 - 2⁶ = 15661004987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15661005071) 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, 2610167506 + ... + 2610167511.

It is an arithmetic number, because the mean of its divisors is an integer number (5220335018).

Almost surely, 2^15661005051 is an apocalyptic number.

15661005051 is a deficient number, since it is larger than the sum of its proper divisors (5220335021).

15661005051 is an equidigital number, since it uses as much as digits as its factorization.

15661005051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5220335020.

The product of its (nonzero) digits is 4500, while the sum is 30.

The spelling of 15661005051 in words is "fifteen billion, six hundred sixty-one million, five thousand, fifty-one".