81432081 has 32 divisors (see below), whose sum is σ = 127836800. Its totient is φ = 51088320.

The previous prime is 81432077. The next prime is 81432083. The reversal of 81432081 is 18023418.

It is not a de Polignac number, because 81432081 - 2² = 81432077 is a prime.

It is a super-2 number, since 2×81432081² = 13262367631981122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81432083) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92415 + ... + 93291.

It is an arithmetic number, because the mean of its divisors is an integer number (3994900).

Almost surely, 2^81432081 is an apocalyptic number.

It is an amenable number.

81432081 is a deficient number, since it is larger than the sum of its proper divisors (46404719).

81432081 is a wasteful number, since it uses less digits than its factorization.

81432081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086 (or 1080 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81432081 is about 9023.9725730966. The cubic root of 81432081 is about 433.4428511486.

Adding to 81432081 its reverse (18023418), we get a palindrome (99455499).

The spelling of 81432081 in words is "eighty-one million, four hundred thirty-two thousand, eighty-one".