16972781 has 16 divisors (see below), whose sum is σ = 20680704. Its totient is φ = 13613424.

The previous prime is 16972771. The next prime is 16972819. The reversal of 16972781 is 18727961.

It is not a de Polignac number, because 16972781 - 2¹⁸ = 16710637 is a prime.

It is a super-2 number, since 2×16972781² = 576150589747922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16972721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6446 + ... + 8688.

It is an arithmetic number, because the mean of its divisors is an integer number (1292544).

Almost surely, 2^16972781 is an apocalyptic number.

It is an amenable number.

16972781 is a deficient number, since it is larger than the sum of its proper divisors (3707923).

16972781 is a wasteful number, since it uses less digits than its factorization.

16972781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2320.

The product of its digits is 42336, while the sum is 41.

The square root of 16972781 is about 4119.8035147322. The cubic root of 16972781 is about 256.9908549487.

The spelling of 16972781 in words is "sixteen million, nine hundred seventy-two thousand, seven hundred eighty-one".