81297100 has 36 divisors (see below), whose sum is σ = 176809864. Its totient is φ = 32446080.

The previous prime is 81297091. The next prime is 81297113. The reversal of 81297100 is 179218.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78184 + ... + 79216.

Almost surely, 2^81297100 is an apocalyptic number.

It is an amenable number.

81297100 is an abundant number, since it is smaller than the sum of its proper divisors (95512764).

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

81297100 is a wasteful number, since it uses less digits than its factorization.

81297100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1834 (or 1827 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 81297100 is about 9016.4904480624. The cubic root of 81297100 is about 433.2032285281.

The spelling of 81297100 in words is "eighty-one million, two hundred ninety-seven thousand, one hundred".