216988397831 has 4 divisors (see below), whose sum is σ = 217273534464. Its totient is φ = 216703261200.

The previous prime is 216988397819. The next prime is 216988397833. The reversal of 216988397831 is 138793889612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 216988397831 - 2³⁰ = 215914656007 is a prime.

It is a super-2 number, since 2×216988397831² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216988397833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142567175 + ... + 142568696.

It is an arithmetic number, because the mean of its divisors is an integer number (54318383616).

Almost surely, 2^216988397831 is an apocalyptic number.

216988397831 is a deficient number, since it is larger than the sum of its proper divisors (285136633).

216988397831 is an equidigital number, since it uses as much as digits as its factorization.

216988397831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285136632.

The product of its digits is 31352832, while the sum is 65.

The spelling of 216988397831 in words is "two hundred sixteen billion, nine hundred eighty-eight million, three hundred ninety-seven thousand, eight hundred thirty-one".