16939821 has 16 divisors (see below), whose sum is σ = 23442048. Its totient is φ = 10872000.

The previous prime is 16939801. The next prime is 16939823. The reversal of 16939821 is 12893961.

It is not a de Polignac number, because 16939821 - 2⁶ = 16939757 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16939821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16939823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10456 + ... + 11966.

It is an arithmetic number, because the mean of its divisors is an integer number (1465128).

Almost surely, 2^16939821 is an apocalyptic number.

It is an amenable number.

16939821 is a deficient number, since it is larger than the sum of its proper divisors (6502227).

16939821 is a wasteful number, since it uses less digits than its factorization.

16939821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1652.

The product of its digits is 23328, while the sum is 39.

The square root of 16939821 is about 4115.8013800474. The cubic root of 16939821 is about 256.8243941608.

The spelling of 16939821 in words is "sixteen million, nine hundred thirty-nine thousand, eight hundred twenty-one".