16421857 has 2 divisors, whose sum is σ = 16421858. Its totient is φ = 16421856.

The previous prime is 16421851. The next prime is 16421863. The reversal of 16421857 is 75812461.

It is a balanced prime because it is at equal distance from previous prime (16421851) and next prime (16421863).

It can be written as a sum of positive squares in only one way, i.e., 11182336 + 5239521 = 3344^2 + 2289^2 .

It is a cyclic number.

It is not a de Polignac number, because 16421857 - 2³ = 16421849 is a prime.

It is not a weakly prime, because it can be changed into another prime (16421851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8210928 + 8210929.

It is an arithmetic number, because the mean of its divisors is an integer number (8210929).

Almost surely, 2^16421857 is an apocalyptic number.

It is an amenable number.

16421857 is a deficient number, since it is larger than the sum of its proper divisors (1).

16421857 is an equidigital number, since it uses as much as digits as its factorization.

16421857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 34.

The square root of 16421857 is about 4052.3890484503. The cubic root of 16421857 is about 254.1796371177.

The spelling of 16421857 in words is "sixteen million, four hundred twenty-one thousand, eight hundred fifty-seven".