81193100 has 18 divisors (see below), whose sum is σ = 176189244. Its totient is φ = 32477200.

The previous prime is 81193043. The next prime is 81193103. The reversal of 81193100 is 139118.

It is a super-2 number, since 2×81193100² = 13184638975220000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81193103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 405866 + ... + 406065.

Almost surely, 2^81193100 is an apocalyptic number.

It is an amenable number.

81193100 is an abundant number, since it is smaller than the sum of its proper divisors (94996144).

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

81193100 is a wasteful number, since it uses less digits than its factorization.

81193100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 811945 (or 811938 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 23.

The square root of 81193100 is about 9010.7213917644. The cubic root of 81193100 is about 433.0184234081.

The spelling of 81193100 in words is "eighty-one million, one hundred ninety-three thousand, one hundred".