16221901 has 2 divisors, whose sum is σ = 16221902. Its totient is φ = 16221900.

The previous prime is 16221889. The next prime is 16221911. The reversal of 16221901 is 10912261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16208676 + 13225 = 4026^2 + 115^2 .

It is an emirp because it is prime and its reverse (10912261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16221901 - 2⁹ = 16221389 is a prime.

It is equal to p_1044463 and since 16221901 and 1044463 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16221911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8110950 + 8110951.

It is an arithmetic number, because the mean of its divisors is an integer number (8110951).

Almost surely, 2^16221901 is an apocalyptic number.

It is an amenable number.

16221901 is a deficient number, since it is larger than the sum of its proper divisors (1).

16221901 is an equidigital number, since it uses as much as digits as its factorization.

16221901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 16221901 is about 4027.6421141904. The cubic root of 16221901 is about 253.1437730526.

It can be divided in two parts, 16221 and 901, that multiplied together give a triangular number (14615121 = T₅₄₀₆).

The spelling of 16221901 in words is "sixteen million, two hundred twenty-one thousand, nine hundred one".