16764721 has 2 divisors, whose sum is σ = 16764722. Its totient is φ = 16764720.

The previous prime is 16764701. The next prime is 16764731. The reversal of 16764721 is 12746761.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13653025 + 3111696 = 3695^2 + 1764^2 .

It is a cyclic number.

It is not a de Polignac number, because 16764721 - 2²³ = 8376113 is a prime.

It is not a weakly prime, because it can be changed into another prime (16764701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8382360 + 8382361.

It is an arithmetic number, because the mean of its divisors is an integer number (8382361).

Almost surely, 2^16764721 is an apocalyptic number.

It is an amenable number.

16764721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16764721 is an equidigital number, since it uses as much as digits as its factorization.

16764721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14112, while the sum is 34.

The square root of 16764721 is about 4094.4744473497. The cubic root of 16764721 is about 255.9364313598.

The spelling of 16764721 in words is "sixteen million, seven hundred sixty-four thousand, seven hundred twenty-one".