218445971 has 4 divisors (see below), whose sum is σ = 231295752. Its totient is φ = 205596192.

The previous prime is 218445967. The next prime is 218446001. The reversal of 218445971 is 179544812.

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 218445971 - 2² = 218445967 is a prime.

It is a super-2 number, since 2×218445971² = 95437284492265682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218445911) 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, 6424865 + ... + 6424898.

It is an arithmetic number, because the mean of its divisors is an integer number (57823938).

Almost surely, 2^218445971 is an apocalyptic number.

218445971 is a deficient number, since it is larger than the sum of its proper divisors (12849781).

218445971 is a wasteful number, since it uses less digits than its factorization.

218445971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12849780.

The product of its digits is 80640, while the sum is 41.

The square root of 218445971 is about 14779.9178279177. The cubic root of 218445971 is about 602.2562925671.

The spelling of 218445971 in words is "two hundred eighteen million, four hundred forty-five thousand, nine hundred seventy-one".