81308700 has 216 divisors, whose sum is σ = 285981696. Its totient is φ = 19152000.

The previous prime is 81308683. The next prime is 81308707. The reversal of 81308700 is 780318.

It is a super-2 number, since 2×81308700² = 13222209391380000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81308707) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 425605 + ... + 425795.

Almost surely, 2^81308700 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81308700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142990848).

81308700 is an abundant number, since it is smaller than the sum of its proper divisors (204672996).

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

81308700 is a wasteful number, since it uses less digits than its factorization.

81308700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265 (or 255 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 81308700 is about 9017.1336909242. The cubic root of 81308700 is about 433.2238316348.

The spelling of 81308700 in words is "eighty-one million, three hundred eight thousand, seven hundred".