81611632 has 20 divisors (see below), whose sum is σ = 160804440. Its totient is φ = 40113728.

The previous prime is 81611531. The next prime is 81611639. The reversal of 81611632 is 23611618.

It is a self number, because there is not a number n which added to its sum of digits gives 81611632.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81611639) 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, 42283 + ... + 44170.

It is an arithmetic number, because the mean of its divisors is an integer number (8040222).

Almost surely, 2^81611632 is an apocalyptic number.

It is an amenable number.

81611632 is a deficient number, since it is larger than the sum of its proper divisors (79192808).

81611632 is a wasteful number, since it uses less digits than its factorization.

81611632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86520 (or 86514 counting only the distinct ones).

The product of its digits is 1728, while the sum is 28.

The square root of 81611632 is about 9033.9156515876. The cubic root of 81611632 is about 433.7611858355.

The spelling of 81611632 in words is "eighty-one million, six hundred eleven thousand, six hundred thirty-two".