16921493 has 2 divisors, whose sum is σ = 16921494. Its totient is φ = 16921492.

The previous prime is 16921447. The next prime is 16921507. The reversal of 16921493 is 39412961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14122564 + 2798929 = 3758^2 + 1673^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16921493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16920493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8460746 + 8460747.

It is an arithmetic number, because the mean of its divisors is an integer number (8460747).

Almost surely, 2^16921493 is an apocalyptic number.

It is an amenable number.

16921493 is a deficient number, since it is larger than the sum of its proper divisors (1).

16921493 is an equidigital number, since it uses as much as digits as its factorization.

16921493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 35.

The square root of 16921493 is about 4113.5742365977. The cubic root of 16921493 is about 256.7317372171.

The spelling of 16921493 in words is "sixteen million, nine hundred twenty-one thousand, four hundred ninety-three".