16445981 has 4 divisors (see below), whose sum is σ = 16459872. Its totient is φ = 16432092.

The previous prime is 16445977. The next prime is 16445999. The reversal of 16445981 is 18954461.

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 not a de Polignac number, because 16445981 - 2² = 16445977 is a prime.

It is a super-2 number, since 2×16445981² = 540940582104722, 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 (16445081) 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, 4985 + ... + 7598.

It is an arithmetic number, because the mean of its divisors is an integer number (4114968).

Almost surely, 2^16445981 is an apocalyptic number.

It is an amenable number.

16445981 is a deficient number, since it is larger than the sum of its proper divisors (13891).

16445981 is a wasteful number, since it uses less digits than its factorization.

16445981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13890.

The product of its digits is 34560, while the sum is 38.

The square root of 16445981 is about 4055.3644719063. The cubic root of 16445981 is about 254.3040410229.

The spelling of 16445981 in words is "sixteen million, four hundred forty-five thousand, nine hundred eighty-one".