81156700 has 36 divisors (see below), whose sum is σ = 178356640. Its totient is φ = 32048640.

The previous prime is 81156637. The next prime is 81156701. The reversal of 81156700 is 765118.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81156701) 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, 2764 + ... + 13036.

Almost surely, 2^81156700 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 81156700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89178320).

81156700 is an abundant number, since it is smaller than the sum of its proper divisors (97199940).

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

81156700 is a wasteful number, since it uses less digits than its factorization.

81156700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10366 (or 10359 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 28.

The square root of 81156700 is about 9008.7013492512. The cubic root of 81156700 is about 432.9537043346.

The spelling of 81156700 in words is "eighty-one million, one hundred fifty-six thousand, seven hundred".