81250100 has 18 divisors (see below), whose sum is σ = 176312934. Its totient is φ = 32500000.

The previous prime is 81250073. The next prime is 81250133. The reversal of 81250100 is 105218.

It can be written as a sum of positive squares in 3 ways, for example, as 178084 + 81072016 = 422^2 + 9004^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 406151 + ... + 406350.

It is an arithmetic number, because the mean of its divisors is an integer number (9795163).

Almost surely, 2^81250100 is an apocalyptic number.

It is an amenable number.

81250100 is an abundant number, since it is smaller than the sum of its proper divisors (95062834).

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

81250100 is a wasteful number, since it uses less digits than its factorization.

81250100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 812515 (or 812508 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 81250100 is about 9013.8837356602. The cubic root of 81250100 is about 433.1197303605.

Adding to 81250100 its reverse (105218), we get a palindrome (81355318).

The spelling of 81250100 in words is "eighty-one million, two hundred fifty thousand, one hundred".