81912450 has 48 divisors (see below), whose sum is σ = 208647360. Its totient is φ = 21251520.

The previous prime is 81912449. The next prime is 81912461. The reversal of 81912450 is 5421918.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon 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 23 ways as a sum of consecutive naturals, for example, 1830 + ... + 12929.

It is an arithmetic number, because the mean of its divisors is an integer number (4346820).

Almost surely, 2^81912450 is an apocalyptic number.

81912450 is an abundant number, since it is smaller than the sum of its proper divisors (126734910).

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

81912450 is a wasteful number, since it uses less digits than its factorization.

81912450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14811 (or 14806 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 81912450 is about 9050.5497070620. The cubic root of 81912450 is about 434.2934758931.

The spelling of 81912450 in words is "eighty-one million, nine hundred twelve thousand, four hundred fifty".