81013536 has 36 divisors (see below), whose sum is σ = 230383062. Its totient is φ = 27004416.

The previous prime is 81013523. The next prime is 81013547. The reversal of 81013536 is 63531018.

It can be written as a sum of positive squares in only one way, i.e., 79923600 + 1089936 = 8940^2 + 1044^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 140361 + ... + 140936.

Almost surely, 2^81013536 is an apocalyptic number.

It is an amenable number.

81013536 is an abundant number, since it is smaller than the sum of its proper divisors (149369526).

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

81013536 is a wasteful number, since it uses less digits than its factorization.

81013536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281313 (or 281302 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 81013536 is about 9000.7519685857. The cubic root of 81013536 is about 432.6989713426.

The spelling of 81013536 in words is "eighty-one million, thirteen thousand, five hundred thirty-six".