16991497 has 2 divisors, whose sum is σ = 16991498. Its totient is φ = 16991496.

The previous prime is 16991467. The next prime is 16991501. The reversal of 16991497 is 79419961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14622976 + 2368521 = 3824^2 + 1539^2 .

It is a cyclic number.

It is not a de Polignac number, because 16991497 - 2⁷ = 16991369 is a prime.

It is not a weakly prime, because it can be changed into another prime (16991437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8495748 + 8495749.

It is an arithmetic number, because the mean of its divisors is an integer number (8495749).

Almost surely, 2^16991497 is an apocalyptic number.

It is an amenable number.

16991497 is a deficient number, since it is larger than the sum of its proper divisors (1).

16991497 is an equidigital number, since it uses as much as digits as its factorization.

16991497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 46.

The square root of 16991497 is about 4122.0743564375. The cubic root of 16991497 is about 257.0852820980.

The spelling of 16991497 in words is "sixteen million, nine hundred ninety-one thousand, four hundred ninety-seven".