16375613981 has 4 divisors (see below), whose sum is σ = 16376785500. Its totient is φ = 16374442464.

The previous prime is 16375613977. The next prime is 16375614001. The reversal of 16375613981 is 18931657361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18931657361 = 19 ⋅996403019.

It can be written as a sum of positive squares in 2 ways, for example, as 12982551481 + 3393062500 = 113941^2 + 58250^2 .

It is a cyclic number.

It is not a de Polignac number, because 16375613981 - 2² = 16375613977 is a prime.

It is a super-2 number, since 2×16375613981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16375613911) 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, 564536 + ... + 592833.

It is an arithmetic number, because the mean of its divisors is an integer number (4094196375).

Almost surely, 2^16375613981 is an apocalyptic number.

It is an amenable number.

16375613981 is a deficient number, since it is larger than the sum of its proper divisors (1171519).

16375613981 is a wasteful number, since it uses less digits than its factorization.

16375613981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1171518.

The product of its digits is 816480, while the sum is 50.

The spelling of 16375613981 in words is "sixteen billion, three hundred seventy-five million, six hundred thirteen thousand, nine hundred eighty-one".