16279981 has 2 divisors, whose sum is σ = 16279982. Its totient is φ = 16279980.

The previous prime is 16279973. The next prime is 16280027. The reversal of 16279981 is 18997261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14945956 + 1334025 = 3866^2 + 1155^2 .

It is a cyclic number.

It is not a de Polignac number, because 16279981 - 2³ = 16279973 is a prime.

It is a super-2 number, since 2×16279981² = 530075562720722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16279481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8139990 + 8139991.

It is an arithmetic number, because the mean of its divisors is an integer number (8139991).

Almost surely, 2^16279981 is an apocalyptic number.

It is an amenable number.

16279981 is a deficient number, since it is larger than the sum of its proper divisors (1).

16279981 is an equidigital number, since it uses as much as digits as its factorization.

16279981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 43.

The square root of 16279981 is about 4034.8458458781. The cubic root of 16279981 is about 253.4455272136.

The spelling of 16279981 in words is "sixteen million, two hundred seventy-nine thousand, nine hundred eighty-one".