16013781 has 40 divisors (see below), whose sum is σ = 27847424. Its totient is φ = 8981280.

The previous prime is 16013749. The next prime is 16013801. The reversal of 16013781 is 18731061.

It is not a de Polignac number, because 16013781 - 2⁵ = 16013749 is a prime.

It is a super-2 number, since 2×16013781² = 512882363831922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16013731) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 34356 + ... + 34818.

Almost surely, 2^16013781 is an apocalyptic number.

It is an amenable number.

16013781 is a deficient number, since it is larger than the sum of its proper divisors (11833643).

16013781 is an equidigital number, since it uses as much as digits as its factorization.

16013781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543 (or 534 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 16013781 is about 4001.7222542300. The cubic root of 16013781 is about 252.0565349348.

The spelling of 16013781 in words is "sixteen million, thirteen thousand, seven hundred eighty-one".