81220850 has 12 divisors (see below), whose sum is σ = 151070874. Its totient is φ = 32488320.

The previous prime is 81220823. The next prime is 81220859. The reversal of 81220850 is 5802218.

It can be written as a sum of positive squares in 3 ways, for example, as 69572281 + 11648569 = 8341^2 + 3413^2 .

It is not an unprimeable number, because it can be changed into a prime (81220859) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 812159 + ... + 812258.

Almost surely, 2^81220850 is an apocalyptic number.

81220850 is a deficient number, since it is larger than the sum of its proper divisors (69850024).

81220850 is a wasteful number, since it uses less digits than its factorization.

81220850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1624429 (or 1624424 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 81220850 is about 9012.2610925339. The cubic root of 81220850 is about 433.0677498186.

The spelling of 81220850 in words is "eighty-one million, two hundred twenty thousand, eight hundred fifty".