81200218 has 32 divisors (see below), whose sum is σ = 135924480. Its totient is φ = 36072960.

The previous prime is 81200209. The next prime is 81200221.

81200218 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 221071 + ... + 221437.

It is an arithmetic number, because the mean of its divisors is an integer number (4247640).

Almost surely, 2^81200218 is an apocalyptic number.

81200218 is a deficient number, since it is larger than the sum of its proper divisors (54724262).

81200218 is a wasteful number, since it uses less digits than its factorization.

81200218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 582.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 81200218 is about 9011.1163570337. The cubic root of 81200218 is about 433.0310769262.

It can be divided in two parts, 81200 and 218, that added together give a palindrome (81418).

The spelling of 81200218 in words is "eighty-one million, two hundred thousand, two hundred eighteen".