15966813901 has 4 divisors (see below), whose sum is σ = 15967241532. Its totient is φ = 15966386272.

The previous prime is 15966813887. The next prime is 15966813937. The reversal of 15966813901 is 10931866951.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10931866951 = 499 ⋅21907549.

It can be written as a sum of positive squares in 2 ways, for example, as 15314062500 + 652751401 = 123750^2 + 25549^2 .

It is a cyclic number.

It is not a de Polignac number, because 15966813901 - 2⁵ = 15966813869 is a prime.

It is a super-2 number, since 2×15966813901² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15966813991) 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, 151816 + ... + 234481.

It is an arithmetic number, because the mean of its divisors is an integer number (3991810383).

Almost surely, 2^15966813901 is an apocalyptic number.

It is an amenable number.

15966813901 is a deficient number, since it is larger than the sum of its proper divisors (427631).

15966813901 is an equidigital number, since it uses as much as digits as its factorization.

15966813901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427630.

The product of its (nonzero) digits is 349920, while the sum is 49.

The spelling of 15966813901 in words is "fifteen billion, nine hundred sixty-six million, eight hundred thirteen thousand, nine hundred one".