16641640 has 32 divisors (see below), whose sum is σ = 39647880. Its totient is φ = 6264832.

The previous prime is 16641617. The next prime is 16641649. The reversal of 16641640 is 4614661.

It can be written as a sum of positive squares in 4 ways, for example, as 16208676 + 432964 = 4026^2 + 658^2 .

It is a junction number, because it is equal to n+sod(n) for n = 16641599 and 16641608.

It is not an unprimeable number, because it can be changed into a prime (16641649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11557 + ... + 12916.

Almost surely, 2^16641640 is an apocalyptic number.

16641640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16641640 is an abundant number, since it is smaller than the sum of its proper divisors (23006240).

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

16641640 is a wasteful number, since it uses less digits than its factorization.

16641640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24501 (or 24497 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 16641640 is about 4079.4166249600. The cubic root of 16641640 is about 255.3085589441.

The spelling of 16641640 in words is "sixteen million, six hundred forty-one thousand, six hundred forty".