81233649 has 12 divisors (see below), whose sum is σ = 134100096. Its totient is φ = 46419192.

The previous prime is 81233627. The next prime is 81233653. The reversal of 81233649 is 94633218.

81233649 is a `hidden beast` number, since 8 + 1 + 2 + 3 + 3 + 649 = 666.

It is not a de Polignac number, because 81233649 - 2⁵ = 81233617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81233699) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 644649 + ... + 644774.

It is an arithmetic number, because the mean of its divisors is an integer number (11175008).

Almost surely, 2^81233649 is an apocalyptic number.

It is an amenable number.

81233649 is a deficient number, since it is larger than the sum of its proper divisors (52866447).

81233649 is a wasteful number, since it uses less digits than its factorization.

81233649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1289436 (or 1289433 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 81233649 is about 9012.9711527332. The cubic root of 81233649 is about 433.0904966174.

The spelling of 81233649 in words is "eighty-one million, two hundred thirty-three thousand, six hundred forty-nine".