16405644 has 12 divisors (see below), whose sum is σ = 38279864. Its totient is φ = 5468544.

The previous prime is 16405643. The next prime is 16405657. The reversal of 16405644 is 44650461.

16405644 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16405643) 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, 683557 + ... + 683580.

Almost surely, 2^16405644 is an apocalyptic number.

It is an amenable number.

16405644 is an abundant number, since it is smaller than the sum of its proper divisors (21874220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16405644 is a wasteful number, since it uses less digits than its factorization.

16405644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1367144 (or 1367142 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 16405644 is about 4050.3881295501. The cubic root of 16405644 is about 254.0959606004.

The spelling of 16405644 in words is "sixteen million, four hundred five thousand, six hundred forty-four".