216971894 has 16 divisors (see below), whose sum is σ = 335586240. Its totient is φ = 105148680.

The previous prime is 216971893. The next prime is 216971897. The reversal of 216971894 is 498179612.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216971893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1637 + ... + 20895.

It is an arithmetic number, because the mean of its divisors is an integer number (20974140).

Almost surely, 2^216971894 is an apocalyptic number.

216971894 is a deficient number, since it is larger than the sum of its proper divisors (118614346).

216971894 is a wasteful number, since it uses less digits than its factorization.

216971894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19435.

The product of its digits is 217728, while the sum is 47.

The square root of 216971894 is about 14729.9658519631. The cubic root of 216971894 is about 600.8985555101.

The spelling of 216971894 in words is "two hundred sixteen million, nine hundred seventy-one thousand, eight hundred ninety-four".