81284144 has 10 divisors (see below), whose sum is σ = 157488060. Its totient is φ = 40642064.

The previous prime is 81284143. The next prime is 81284167. The reversal of 81284144 is 44148218.

It is a super-2 number, since 2×81284144² = 13214224131625472, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 81284144.

It is not an unprimeable number, because it can be changed into a prime (81284143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2540114 + ... + 2540145.

It is an arithmetic number, because the mean of its divisors is an integer number (15748806).

Almost surely, 2^81284144 is an apocalyptic number.

It is an amenable number.

81284144 is a deficient number, since it is larger than the sum of its proper divisors (76203916).

81284144 is a wasteful number, since it uses less digits than its factorization.

81284144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5080267 (or 5080261 counting only the distinct ones).

The product of its digits is 8192, while the sum is 32.

The square root of 81284144 is about 9015.7719580744. The cubic root of 81284144 is about 433.1802146723.

The spelling of 81284144 in words is "eighty-one million, two hundred eighty-four thousand, one hundred forty-four".