81284261 has 8 divisors (see below), whose sum is σ = 85802880. Its totient is φ = 76789728.

The previous prime is 81284257. The next prime is 81284309. The reversal of 81284261 is 16248218.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81284261 - 2² = 81284257 is a prime.

It is a super-2 number, since 2×81284261² = 13214262172632242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81284221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1145 + ... + 12801.

It is an arithmetic number, because the mean of its divisors is an integer number (10725360).

Almost surely, 2^81284261 is an apocalyptic number.

It is an amenable number.

81284261 is a deficient number, since it is larger than the sum of its proper divisors (4518619).

81284261 is a wasteful number, since it uses less digits than its factorization.

81284261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12043.

The product of its digits is 6144, while the sum is 32.

The square root of 81284261 is about 9015.7784467011. The cubic root of 81284261 is about 433.1804225114.

The spelling of 81284261 in words is "eighty-one million, two hundred eighty-four thousand, two hundred sixty-one".