15944909891 has 4 divisors (see below), whose sum is σ = 16494734400. Its totient is φ = 15395085384.

The previous prime is 15944909887. The next prime is 15944909917. The reversal of 15944909891 is 19890944951.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 15944909891 - 2² = 15944909887 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 15944909891.

It is not an unprimeable number, because it can be changed into a prime (15944909291) 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, 274912211 + ... + 274912268.

It is an arithmetic number, because the mean of its divisors is an integer number (4123683600).

Almost surely, 2^15944909891 is an apocalyptic number.

15944909891 is a deficient number, since it is larger than the sum of its proper divisors (549824509).

15944909891 is an equidigital number, since it uses as much as digits as its factorization.

15944909891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549824508.

The product of its (nonzero) digits is 4199040, while the sum is 59.

The spelling of 15944909891 in words is "fifteen billion, nine hundred forty-four million, nine hundred nine thousand, eight hundred ninety-one".