81807700 has 36 divisors (see below), whose sum is σ = 191181340. Its totient is φ = 30205440.

The previous prime is 81807697. The next prime is 81807701. The reversal of 81807700 is 770818.

It can be written as a sum of positive squares in 6 ways, for example, as 4613904 + 77193796 = 2148^2 + 8786^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81807701) 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, 30165 + ... + 32764.

Almost surely, 2^81807700 is an apocalyptic number.

It is an amenable number.

81807700 is an abundant number, since it is smaller than the sum of its proper divisors (109373640).

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

81807700 is a wasteful number, since it uses less digits than its factorization.

81807700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62956 (or 62949 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 31.

The square root of 81807700 is about 9044.7609144742. The cubic root of 81807700 is about 434.1082714572.

The spelling of 81807700 in words is "eighty-one million, eight hundred seven thousand, seven hundred".