16997981 has 16 divisors (see below), whose sum is σ = 22823808. Its totient is φ = 12225600.

The previous prime is 16997963. The next prime is 16997993. The reversal of 16997981 is 18979961.

It is a cyclic number.

It is not a de Polignac number, because 16997981 - 2⁶ = 16997917 is a prime.

It is a super-2 number, since 2×16997981² = 577862716152722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16997921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7490 + ... + 9491.

It is an arithmetic number, because the mean of its divisors is an integer number (1426488).

Almost surely, 2^16997981 is an apocalyptic number.

16997981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16997981 is a deficient number, since it is larger than the sum of its proper divisors (5825827).

16997981 is a wasteful number, since it uses less digits than its factorization.

16997981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17012.

The product of its digits is 244944, while the sum is 50.

The square root of 16997981 is about 4122.8607786342. The cubic root of 16997981 is about 257.1179794128.

The spelling of 16997981 in words is "sixteen million, nine hundred ninety-seven thousand, nine hundred eighty-one".