16221761 has 2 divisors, whose sum is σ = 16221762. Its totient is φ = 16221760.

The previous prime is 16221749. The next prime is 16221823. The reversal of 16221761 is 16712261.

16221761 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14205361 + 2016400 = 3769^2 + 1420^2 .

It is an emirp because it is prime and its reverse (16712261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16221761 - 2⁶ = 16221697 is a prime.

It is a super-2 number, since 2×16221761² = 526291059882242, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 16221761.

It is not a weakly prime, because it can be changed into another prime (16221061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8110880 + 8110881.

It is an arithmetic number, because the mean of its divisors is an integer number (8110881).

Almost surely, 2^16221761 is an apocalyptic number.

It is an amenable number.

16221761 is a deficient number, since it is larger than the sum of its proper divisors (1).

16221761 is an equidigital number, since it uses as much as digits as its factorization.

16221761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 26.

The square root of 16221761 is about 4027.6247342572. The cubic root of 16221761 is about 253.1430448143.

The spelling of 16221761 in words is "sixteen million, two hundred twenty-one thousand, seven hundred sixty-one".