218020491 has 40 divisors (see below), whose sum is σ = 352853424. Its totient is φ = 133358400.

The previous prime is 218020483. The next prime is 218020513. The reversal of 218020491 is 194020812.

It is not a de Polignac number, because 218020491 - 2³ = 218020483 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (218020471) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 206916 + ... + 207966.

Almost surely, 2^218020491 is an apocalyptic number.

218020491 is a deficient number, since it is larger than the sum of its proper divisors (134832933).

218020491 is a wasteful number, since it uses less digits than its factorization.

218020491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273 (or 1264 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 218020491 is about 14765.5169567476. The cubic root of 218020491 is about 601.8650218161.

The spelling of 218020491 in words is "two hundred eighteen million, twenty thousand, four hundred ninety-one".