81540236 has 6 divisors (see below), whose sum is σ = 142695420. Its totient is φ = 40770116.

The previous prime is 81540233. The next prime is 81540241. The reversal of 81540236 is 63204518.

It is a junction number, because it is equal to n+sod(n) for n = 81540199 and 81540208.

It is not an unprimeable number, because it can be changed into a prime (81540233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10192526 + ... + 10192533.

It is an arithmetic number, because the mean of its divisors is an integer number (23782570).

Almost surely, 2^81540236 is an apocalyptic number.

It is an amenable number.

81540236 is a deficient number, since it is larger than the sum of its proper divisors (61155184).

81540236 is a wasteful number, since it uses less digits than its factorization.

81540236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20385063 (or 20385061 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 81540236 is about 9029.9632335907. The cubic root of 81540236 is about 433.6346603716.

The spelling of 81540236 in words is "eighty-one million, five hundred forty thousand, two hundred thirty-six".