16311821 has 2 divisors, whose sum is σ = 16311822. Its totient is φ = 16311820.

The previous prime is 16311791. The next prime is 16311851. The reversal of 16311821 is 12811361.

It is a balanced prime because it is at equal distance from previous prime (16311791) and next prime (16311851).

It can be written as a sum of positive squares in only one way, i.e., 13032100 + 3279721 = 3610^2 + 1811^2 .

It is a cyclic number.

It is not a de Polignac number, because 16311821 - 2²² = 12117517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16311851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8155910 + 8155911.

It is an arithmetic number, because the mean of its divisors is an integer number (8155911).

Almost surely, 2^16311821 is an apocalyptic number.

It is an amenable number.

16311821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16311821 is an equidigital number, since it uses as much as digits as its factorization.

16311821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 23.

The square root of 16311821 is about 4038.7895463864. The cubic root of 16311821 is about 253.6106471943.

The spelling of 16311821 in words is "sixteen million, three hundred eleven thousand, eight hundred twenty-one".