16910021 has 4 divisors (see below), whose sum is σ = 17229132. Its totient is φ = 16590912.

The previous prime is 16910011. The next prime is 16910027. The reversal of 16910021 is 12001961.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15100996 + 1809025 = 3886^2 + 1345^2 .

It is a cyclic number.

It is not a de Polignac number, because 16910021 - 2⁶ = 16909957 is a prime.

It is a pancake number, because a pancake can be divided into 16910021 parts by 5815 straight cuts.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 16909975 and 16910002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16910027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159476 + ... + 159581.

It is an arithmetic number, because the mean of its divisors is an integer number (4307283).

Almost surely, 2^16910021 is an apocalyptic number.

It is an amenable number.

16910021 is a deficient number, since it is larger than the sum of its proper divisors (319111).

16910021 is an equidigital number, since it uses as much as digits as its factorization.

16910021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319110.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 16910021 is about 4112.1795923816. The cubic root of 16910021 is about 256.6737066340.

Adding to 16910021 its reverse (12001961), we get a palindrome (28911982).

The spelling of 16910021 in words is "sixteen million, nine hundred ten thousand, twenty-one".