81406368 has 36 divisors (see below), whose sum is σ = 231500178. Its totient is φ = 27135360.

The previous prime is 81406343. The next prime is 81406417. The reversal of 81406368 is 86360418.

It is a happy number.

81406368 is a `hidden beast` number, since 8 + 14 + 0 + 636 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 68359824 + 13046544 = 8268^2 + 3612^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 141043 + ... + 141618.

Almost surely, 2^81406368 is an apocalyptic number.

It is an amenable number.

81406368 is an abundant number, since it is smaller than the sum of its proper divisors (150093810).

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

81406368 is a wasteful number, since it uses less digits than its factorization.

81406368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282677 (or 282666 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 81406368 is about 9022.5477554846. The cubic root of 81406368 is about 433.3972250302.

The spelling of 81406368 in words is "eighty-one million, four hundred six thousand, three hundred sixty-eight".