15966950921 has 4 divisors (see below), whose sum is σ = 16092675072. Its totient is φ = 15841226772.

The previous prime is 15966950893. The next prime is 15966950977. The reversal of 15966950921 is 12905966951.

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 a de Polignac number, because none of the positive numbers 2^k-15966950921 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (15966950981) 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, 62861885 + ... + 62862138.

It is an arithmetic number, because the mean of its divisors is an integer number (4023168768).

Almost surely, 2^15966950921 is an apocalyptic number.

It is an amenable number.

15966950921 is a deficient number, since it is larger than the sum of its proper divisors (125724151).

15966950921 is a wasteful number, since it uses less digits than its factorization.

15966950921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125724150.

The product of its (nonzero) digits is 1312200, while the sum is 53.

The spelling of 15966950921 in words is "fifteen billion, nine hundred sixty-six million, nine hundred fifty thousand, nine hundred twenty-one".