81271636 has 12 divisors (see below), whose sum is σ = 143555328. Its totient is φ = 40255832.

The previous prime is 81271633. The next prime is 81271643. The reversal of 81271636 is 63617218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81271633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94516 + ... + 95371.

It is an arithmetic number, because the mean of its divisors is an integer number (11962944).

Almost surely, 2^81271636 is an apocalyptic number.

It is an amenable number.

81271636 is a deficient number, since it is larger than the sum of its proper divisors (62283692).

81271636 is a wasteful number, since it uses less digits than its factorization.

81271636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189998 (or 189996 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 81271636 is about 9015.0782581185. The cubic root of 81271636 is about 433.1579942826.

The spelling of 81271636 in words is "eighty-one million, two hundred seventy-one thousand, six hundred thirty-six".