216971493 has 16 divisors (see below), whose sum is σ = 307262016. Its totient is φ = 135717120.

The previous prime is 216971483. The next prime is 216971509. The reversal of 216971493 is 394179612.

It is not a de Polignac number, because 216971493 - 2⁴ = 216971477 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216971423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10455 + ... + 23307.

It is an arithmetic number, because the mean of its divisors is an integer number (19203876).

Almost surely, 2^216971493 is an apocalyptic number.

It is an amenable number.

216971493 is a deficient number, since it is larger than the sum of its proper divisors (90290523).

216971493 is a wasteful number, since it uses less digits than its factorization.

216971493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13204.

The product of its digits is 81648, while the sum is 42.

The square root of 216971493 is about 14729.9522402484. The cubic root of 216971493 is about 600.8981853232.

The spelling of 216971493 in words is "two hundred sixteen million, nine hundred seventy-one thousand, four hundred ninety-three".