16220381 has 4 divisors (see below), whose sum is σ = 16442652. Its totient is φ = 15998112.

The previous prime is 16220371. The next prime is 16220383. The reversal of 16220381 is 18302261.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12355225 + 3865156 = 3515^2 + 1966^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16220381 is a prime.

It is a super-2 number, since 2×16220381² = 526201519570322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16220383) 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, 111026 + ... + 111171.

It is an arithmetic number, because the mean of its divisors is an integer number (4110663).

Almost surely, 2^16220381 is an apocalyptic number.

It is an amenable number.

16220381 is a deficient number, since it is larger than the sum of its proper divisors (222271).

16220381 is an equidigital number, since it uses as much as digits as its factorization.

16220381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222270.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 16220381 is about 4027.4534137591. The cubic root of 16220381 is about 253.1358662408.

The spelling of 16220381 in words is "sixteen million, two hundred twenty thousand, three hundred eighty-one".