216403881 has 8 divisors (see below), whose sum is σ = 288661824. Its totient is φ = 144207600.

The previous prime is 216403843. The next prime is 216403919. The reversal of 216403881 is 188304612.

It is an interprime number because it is at equal distance from previous prime (216403843) and next prime (216403919).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 216403881 - 2⁷ = 216403753 is a prime.

It is a super-2 number, since 2×216403881² = 93661279423724322, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (216403801) 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, 6486 + ... + 21791.

It is an arithmetic number, because the mean of its divisors is an integer number (36082728).

Almost surely, 2^216403881 is an apocalyptic number.

It is an amenable number.

216403881 is a deficient number, since it is larger than the sum of its proper divisors (72257943).

216403881 is a wasteful number, since it uses less digits than its factorization.

216403881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30831.

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 216403881 is about 14710.6723503720. The cubic root of 216403881 is about 600.3737310491.

The spelling of 216403881 in words is "two hundred sixteen million, four hundred three thousand, eight hundred eighty-one".