81133564 has 6 divisors (see below), whose sum is σ = 141983744. Its totient is φ = 40566780.

The previous prime is 81133543. The next prime is 81133567. The reversal of 81133564 is 46533118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81133567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10141692 + ... + 10141699.

Almost surely, 2^81133564 is an apocalyptic number.

It is an amenable number.

81133564 is a deficient number, since it is larger than the sum of its proper divisors (60850180).

81133564 is a wasteful number, since it uses less digits than its factorization.

81133564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20283395 (or 20283393 counting only the distinct ones).

The product of its digits is 8640, while the sum is 31.

The square root of 81133564 is about 9007.4171658695. The cubic root of 81133564 is about 432.9125585474.

The spelling of 81133564 in words is "eighty-one million, one hundred thirty-three thousand, five hundred sixty-four".