16978399 has 2 divisors, whose sum is σ = 16978400. Its totient is φ = 16978398.

The previous prime is 16978373. The next prime is 16978411. The reversal of 16978399 is 99387961.

It is a strong prime.

It is an emirp because it is prime and its reverse (99387961) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16978399 - 2⁷ = 16978271 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16978309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8489199 + 8489200.

It is an arithmetic number, because the mean of its divisors is an integer number (8489200).

Almost surely, 2^16978399 is an apocalyptic number.

16978399 is a deficient number, since it is larger than the sum of its proper divisors (1).

16978399 is an equidigital number, since it uses as much as digits as its factorization.

16978399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 734832, while the sum is 52.

The square root of 16978399 is about 4120.4852869535. The cubic root of 16978399 is about 257.0192065264.

The spelling of 16978399 in words is "sixteen million, nine hundred seventy-eight thousand, three hundred ninety-nine".