218861352491 has 16 divisors (see below), whose sum is σ = 224994883680. Its totient is φ = 212811187200.

The previous prime is 218861352467. The next prime is 218861352497. The reversal of 218861352491 is 194253168812.

It is a cyclic number.

It is not a de Polignac number, because 218861352491 - 2²² = 218857158187 is a prime.

It is a super-2 number, since 2×218861352491² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218861352497) 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, 10869365 + ... + 10889481.

It is an arithmetic number, because the mean of its divisors is an integer number (14062180230).

Almost surely, 2^218861352491 is an apocalyptic number.

218861352491 is a deficient number, since it is larger than the sum of its proper divisors (6133531189).

218861352491 is a wasteful number, since it uses less digits than its factorization.

218861352491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22174.

The product of its digits is 829440, while the sum is 50.

The spelling of 218861352491 in words is "two hundred eighteen billion, eight hundred sixty-one million, three hundred fifty-two thousand, four hundred ninety-one".