81205722 has 24 divisors (see below), whose sum is σ = 189480564. Its totient is φ = 24986304.

The previous prime is 81205693. The next prime is 81205727. The reversal of 81205722 is 22750218.

It can be written as a sum of positive squares in 2 ways, for example, as 76370121 + 4835601 = 8739^2 + 2199^2 .

It is not an unprimeable number, because it can be changed into a prime (81205727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 173283 + ... + 173750.

Almost surely, 2^81205722 is an apocalyptic number.

81205722 is an abundant number, since it is smaller than the sum of its proper divisors (108274842).

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

81205722 is a wasteful number, since it uses less digits than its factorization.

81205722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347054 (or 347051 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 81205722 is about 9011.4217524206. The cubic root of 81205722 is about 433.0408607636.

The spelling of 81205722 in words is "eighty-one million, two hundred five thousand, seven hundred twenty-two".