81933642 has 96 divisors (see below), whose sum is σ = 222393600. Its totient is φ = 21256704.

The previous prime is 81933629. The next prime is 81933647. The reversal of 81933642 is 24633918.

81933642 is a `hidden beast` number, since 8 + 1 + 9 + 3 + 3 + 642 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 81933597 and 81933606.

It is not an unprimeable number, because it can be changed into a prime (81933647) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 61459 + ... + 62777.

It is an arithmetic number, because the mean of its divisors is an integer number (2316600).

Almost surely, 2^81933642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81933642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111196800).

81933642 is an abundant number, since it is smaller than the sum of its proper divisors (140459958).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81933642 is a wasteful number, since it uses less digits than its factorization.

81933642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1380 (or 1377 counting only the distinct ones).

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

The square root of 81933642 is about 9051.7203889647. The cubic root of 81933642 is about 434.3309254454.

The spelling of 81933642 in words is "eighty-one million, nine hundred thirty-three thousand, six hundred forty-two".