81220278 has 16 divisors (see below), whose sum is σ = 163030320. Its totient is φ = 26975136.

The previous prime is 81220273. The next prime is 81220289. The reversal of 81220278 is 87202218.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81220273) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22773 + ... + 26096.

It is an arithmetic number, because the mean of its divisors is an integer number (10189395).

Almost surely, 2^81220278 is an apocalyptic number.

81220278 is an abundant number, since it is smaller than the sum of its proper divisors (81810042).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81220278 is a wasteful number, since it uses less digits than its factorization.

81220278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49151.

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 81220278 is about 9012.2293579336. The cubic root of 81220278 is about 433.0667331858.

The spelling of 81220278 in words is "eighty-one million, two hundred twenty thousand, two hundred seventy-eight".