16957921 has 2 divisors, whose sum is σ = 16957922. Its totient is φ = 16957920.

The previous prime is 16957909. The next prime is 16957949. The reversal of 16957921 is 12975961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16900321 + 57600 = 4111^2 + 240^2 .

It is an emirp because it is prime and its reverse (12975961) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16957921 - 2²³ = 8569313 is a prime.

It is not a weakly prime, because it can be changed into another prime (16957991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8478960 + 8478961.

It is an arithmetic number, because the mean of its divisors is an integer number (8478961).

Almost surely, 2^16957921 is an apocalyptic number.

It is an amenable number.

16957921 is a deficient number, since it is larger than the sum of its proper divisors (1).

16957921 is an equidigital number, since it uses as much as digits as its factorization.

16957921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34020, while the sum is 40.

The square root of 16957921 is about 4117.9996357455. Note that the first 3 decimals coincide. The cubic root of 16957921 is about 256.9158328854.

The spelling of 16957921 in words is "sixteen million, nine hundred fifty-seven thousand, nine hundred twenty-one".