16321640 has 16 divisors (see below), whose sum is σ = 36723780. Its totient is φ = 6528640.

The previous prime is 16321633. The next prime is 16321667. The reversal of 16321640 is 4612361.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14915044 + 1406596 = 3862^2 + 1186^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203981 + ... + 204060.

Almost surely, 2^16321640 is an apocalyptic number.

16321640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16321640 is an abundant number, since it is smaller than the sum of its proper divisors (20402140).

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

16321640 is a wasteful number, since it uses less digits than its factorization.

16321640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408052 (or 408048 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 16321640 is about 4040.0049504920. The cubic root of 16321640 is about 253.6615244783.

It can be divided in two parts, 16321 and 640, that added together give a palindrome (16961).

The spelling of 16321640 in words is "sixteen million, three hundred twenty-one thousand, six hundred forty".