218771481 has 4 divisors (see below), whose sum is σ = 291695312. Its totient is φ = 145847652.

The previous prime is 218771479. The next prime is 218771489. The reversal of 218771481 is 184177812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 218771481 - 2¹ = 218771479 is a prime.

It is a super-2 number, since 2×218771481² = 95721921797866722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218771489) 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, 36461911 + ... + 36461916.

It is an arithmetic number, because the mean of its divisors is an integer number (72923828).

Almost surely, 2^218771481 is an apocalyptic number.

It is an amenable number.

218771481 is a deficient number, since it is larger than the sum of its proper divisors (72923831).

218771481 is an equidigital number, since it uses as much as digits as its factorization.

218771481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72923830.

The product of its digits is 25088, while the sum is 39.

The square root of 218771481 is about 14790.9256302640. The cubic root of 218771481 is about 602.5552881662. Note that the first 3 decimals are identical.

The spelling of 218771481 in words is "two hundred eighteen million, seven hundred seventy-one thousand, four hundred eighty-one".