16921901 has 2 divisors, whose sum is σ = 16921902. Its totient is φ = 16921900.

The previous prime is 16921867. The next prime is 16921903. The reversal of 16921901 is 10912961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14668900 + 2253001 = 3830^2 + 1501^2 .

It is a cyclic number.

It is not a de Polignac number, because 16921901 - 2²² = 12727597 is a prime.

Together with 16921903, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16921903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8460950 + 8460951.

It is an arithmetic number, because the mean of its divisors is an integer number (8460951).

Almost surely, 2^16921901 is an apocalyptic number.

It is an amenable number.

16921901 is a deficient number, since it is larger than the sum of its proper divisors (1).

16921901 is an equidigital number, since it uses as much as digits as its factorization.

16921901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 16921901 is about 4113.6238282079. The cubic root of 16921901 is about 256.7338005832.

The spelling of 16921901 in words is "sixteen million, nine hundred twenty-one thousand, nine hundred one".