81817284 has 12 divisors (see below), whose sum is σ = 190907024. Its totient is φ = 27272424.

The previous prime is 81817259. The next prime is 81817289. The reversal of 81817284 is 48271818.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×81817284² = 13388135922273312, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81817289) 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, 3409042 + ... + 3409065.

Almost surely, 2^81817284 is an apocalyptic number.

It is an amenable number.

81817284 is an abundant number, since it is smaller than the sum of its proper divisors (109089740).

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

81817284 is a wasteful number, since it uses less digits than its factorization.

81817284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6818114 (or 6818112 counting only the distinct ones).

The product of its digits is 28672, while the sum is 39.

The square root of 81817284 is about 9045.2907084294. The cubic root of 81817284 is about 434.1252231264.

The spelling of 81817284 in words is "eighty-one million, eight hundred seventeen thousand, two hundred eighty-four".