216860491 has 16 divisors (see below), whose sum is σ = 233985024. Its totient is φ = 200489344.

The previous prime is 216860473. The next prime is 216860503. The reversal of 216860491 is 194068612.

It is a happy number.

It is not a de Polignac number, because 216860491 - 2²³ = 208471883 is a prime.

It is a super-2 number, since 2×216860491² = 94056945113522162, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 216860491.

It is not an unprimeable number, because it can be changed into a prime (216860401) 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, 88515 + ... + 90931.

It is an arithmetic number, because the mean of its divisors is an integer number (14624064).

Almost surely, 2^216860491 is an apocalyptic number.

216860491 is a deficient number, since it is larger than the sum of its proper divisors (17124533).

216860491 is a wasteful number, since it uses less digits than its factorization.

216860491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2570.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 216860491 is about 14726.1838573338. The cubic root of 216860491 is about 600.7956952413.

The spelling of 216860491 in words is "two hundred sixteen million, eight hundred sixty thousand, four hundred ninety-one".