16777421 has 2 divisors, whose sum is σ = 16777422. Its totient is φ = 16777420.

The previous prime is 16777381. The next prime is 16777441. The reversal of 16777421 is 12477761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16564900 + 212521 = 4070^2 + 461^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16777421 is a prime.

It is a super-2 number, since 2×16777421² = 562963710822482, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16777441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8388710 + 8388711.

It is an arithmetic number, because the mean of its divisors is an integer number (8388711).

Almost surely, 2^16777421 is an apocalyptic number.

It is an amenable number.

16777421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16777421 is an equidigital number, since it uses as much as digits as its factorization.

16777421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16464, while the sum is 35.

The square root of 16777421 is about 4096.0250243376. The cubic root of 16777421 is about 256.0010426797.

The spelling of 16777421 in words is "sixteen million, seven hundred seventy-seven thousand, four hundred twenty-one".