16872021 has 6 divisors (see below), whose sum is σ = 24370710. Its totient is φ = 11248008.

The previous prime is 16872017. The next prime is 16872047. The reversal of 16872021 is 12027861.

It can be written as a sum of positive squares in only one way, i.e., 16719921 + 152100 = 4089^2 + 390^2 .

It is not a de Polignac number, because 16872021 - 2² = 16872017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16872071) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 937326 + ... + 937343.

It is an arithmetic number, because the mean of its divisors is an integer number (4061785).

Almost surely, 2^16872021 is an apocalyptic number.

It is an amenable number.

16872021 is a deficient number, since it is larger than the sum of its proper divisors (7498689).

16872021 is a wasteful number, since it uses less digits than its factorization.

16872021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1874675 (or 1874672 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 16872021 is about 4107.5565729519. The cubic root of 16872021 is about 256.4812977256.

Adding to 16872021 its reverse (12027861), we get a palindrome (28899882).

The spelling of 16872021 in words is "sixteen million, eight hundred seventy-two thousand, twenty-one".