16721838 has 36 divisors (see below), whose sum is σ = 42148080. Its totient is φ = 4777416.

The previous prime is 16721833. The next prime is 16721899. The reversal of 16721838 is 83812761.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16721833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 8598 + ... + 10361.

It is an arithmetic number, because the mean of its divisors is an integer number (1170780).

Almost surely, 2^16721838 is an apocalyptic number.

16721838 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

16721838 is an abundant number, since it is smaller than the sum of its proper divisors (25426242).

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

16721838 is a wasteful number, since it uses less digits than its factorization.

16721838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18981 (or 18971 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 16721838 is about 4089.2344026725. The cubic root of 16721838 is about 255.7180224493.

The spelling of 16721838 in words is "sixteen million, seven hundred twenty-one thousand, eight hundred thirty-eight".