81533836 has 36 divisors (see below), whose sum is σ = 152716536. Its totient is φ = 38080000.

The previous prime is 81533833. The next prime is 81533839. The reversal of 81533836 is 63833518.

It is an interprime number because it is at equal distance from previous prime (81533833) and next prime (81533839).

It is a junction number, because it is equal to n+sod(n) for n = 81533795 and 81533804.

It is not an unprimeable number, because it can be changed into a prime (81533831) 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 11 ways as a sum of consecutive naturals, for example, 290016 + ... + 290296.

It is an arithmetic number, because the mean of its divisors is an integer number (4242126).

Almost surely, 2^81533836 is an apocalyptic number.

It is an amenable number.

81533836 is a deficient number, since it is larger than the sum of its proper divisors (71182700).

81533836 is a wasteful number, since it uses less digits than its factorization.

81533836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570 (or 551 counting only the distinct ones).

The product of its digits is 51840, while the sum is 37.

The square root of 81533836 is about 9029.6088508861. The cubic root of 81533836 is about 433.6233149117.

It can be divided in two parts, 81533 and 836, that added together give a square (82369 = 287²).

The spelling of 81533836 in words is "eighty-one million, five hundred thirty-three thousand, eight hundred thirty-six".