81533898 has 16 divisors (see below), whose sum is σ = 181186560. Its totient is φ = 27177948.

The previous prime is 81533867. The next prime is 81533911. The reversal of 81533898 is 89833518.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 754890 + ... + 754997.

It is an arithmetic number, because the mean of its divisors is an integer number (11324160).

Almost surely, 2^81533898 is an apocalyptic number.

81533898 is an abundant number, since it is smaller than the sum of its proper divisors (99652662).

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

81533898 is a wasteful number, since it uses less digits than its factorization.

81533898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1509898 (or 1509892 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 81533898 is about 9029.6122840352. The cubic root of 81533898 is about 433.6234248237.

The spelling of 81533898 in words is "eighty-one million, five hundred thirty-three thousand, eight hundred ninety-eight".