16992421 has 2 divisors, whose sum is σ = 16992422. Its totient is φ = 16992420.

The previous prime is 16992419. The next prime is 16992431. The reversal of 16992421 is 12429961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16695396 + 297025 = 4086^2 + 545^2 .

It is a cyclic number.

It is not a de Polignac number, because 16992421 - 2¹ = 16992419 is a prime.

Together with 16992419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16992431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8496210 + 8496211.

It is an arithmetic number, because the mean of its divisors is an integer number (8496211).

Almost surely, 2^16992421 is an apocalyptic number.

It is an amenable number.

16992421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16992421 is an equidigital number, since it uses as much as digits as its factorization.

16992421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 34.

The square root of 16992421 is about 4122.1864344059. The cubic root of 16992421 is about 257.0899421248.

The spelling of 16992421 in words is "sixteen million, nine hundred ninety-two thousand, four hundred twenty-one".