81491814 has 24 divisors (see below), whose sum is σ = 176812272. Its totient is φ = 27126000.

The previous prime is 81491801. The next prime is 81491833. The reversal of 81491814 is 41819418.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12064 + ... + 17564.

It is an arithmetic number, because the mean of its divisors is an integer number (7367178).

Almost surely, 2^81491814 is an apocalyptic number.

81491814 is an abundant number, since it is smaller than the sum of its proper divisors (95320458).

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

81491814 is a wasteful number, since it uses less digits than its factorization.

81491814 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6332 (or 6329 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 81491814 is about 9027.2816506410. The cubic root of 81491814 is about 433.5488065800.

The spelling of 81491814 in words is "eighty-one million, four hundred ninety-one thousand, eight hundred fourteen".