81842840 has 32 divisors (see below), whose sum is σ = 185226480. Its totient is φ = 32545152.

The previous prime is 81842833. The next prime is 81842863. The reversal of 81842840 is 4824818.

It is a self number, because there is not a number n which added to its sum of digits gives 81842840.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 1007 + ... + 12833.

Almost surely, 2^81842840 is an apocalyptic number.

It is an amenable number.

81842840 is an abundant number, since it is smaller than the sum of its proper divisors (103383640).

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

81842840 is a wasteful number, since it uses less digits than its factorization.

81842840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12011 (or 12007 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 35.

The square root of 81842840 is about 9046.7032669365. The cubic root of 81842840 is about 434.1704187490.

The spelling of 81842840 in words is "eighty-one million, eight hundred forty-two thousand, eight hundred forty".