81407790 has 24 divisors (see below), whose sum is σ = 211660488. Its totient is φ = 21708720.

The previous prime is 81407783. The next prime is 81407791. The reversal of 81407790 is 9770418.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81407791) 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, 452176 + ... + 452355.

It is an arithmetic number, because the mean of its divisors is an integer number (8819187).

Almost surely, 2^81407790 is an apocalyptic number.

81407790 is an abundant number, since it is smaller than the sum of its proper divisors (130252698).

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

81407790 is a wasteful number, since it uses less digits than its factorization.

81407790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 904544 (or 904541 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 81407790 is about 9022.6265577159. The cubic root of 81407790 is about 433.3997485317.

The spelling of 81407790 in words is "eighty-one million, four hundred seven thousand, seven hundred ninety".