81255218 has 16 divisors (see below), whose sum is σ = 133104384. Its totient is φ = 36894960.

The previous prime is 81255203. The next prime is 81255221.

It is a happy number.

81255218 is nontrivially palindromic in base 10.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33296 + ... + 35652.

It is an arithmetic number, because the mean of its divisors is an integer number (8319024).

Almost surely, 2^81255218 is an apocalyptic number.

81255218 is a deficient number, since it is larger than the sum of its proper divisors (51849166).

81255218 is a wasteful number, since it uses less digits than its factorization.

81255218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3937.

The product of its digits is 6400, while the sum is 32.

The square root of 81255218 is about 9014.1676265754. The cubic root of 81255218 is about 433.1288243400.

It can be divided in two parts, 812552 and 18, that multiplied together give a triangular number (14625936 = T₅₄₀₈).

The spelling of 81255218 in words is "eighty-one million, two hundred fifty-five thousand, two hundred eighteen".