81432999 has 16 divisors (see below), whose sum is σ = 123210240. Its totient is φ = 53132760.

The previous prime is 81432991. The next prime is 81433019. The reversal of 81432999 is 99923418.

It is not a de Polignac number, because 81432999 - 2³ = 81432991 is a prime.

It is a super-2 number, since 2×81432999² = 13262666652268002, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81432991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30817 + ... + 33354.

It is an arithmetic number, because the mean of its divisors is an integer number (7700640).

Almost surely, 2^81432999 is an apocalyptic number.

81432999 is a deficient number, since it is larger than the sum of its proper divisors (41777241).

81432999 is a wasteful number, since it uses less digits than its factorization.

81432999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64227 (or 64221 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 81432999 is about 9024.0234374696. The cubic root of 81432999 is about 433.4444799049. Note that the first 4 decimals are identical.

The spelling of 81432999 in words is "eighty-one million, four hundred thirty-two thousand, nine hundred ninety-nine".