81428436 has 48 divisors (see below), whose sum is σ = 223534080. Its totient is φ = 25545600.

The previous prime is 81428407. The next prime is 81428467. The reversal of 81428436 is 63482418.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81428436.

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 15 ways as a sum of consecutive naturals, for example, 20340 + ... + 24011.

It is an arithmetic number, because the mean of its divisors is an integer number (4656960).

Almost surely, 2^81428436 is an apocalyptic number.

It is an amenable number.

81428436 is an abundant number, since it is smaller than the sum of its proper divisors (142105644).

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

81428436 is a wasteful number, since it uses less digits than its factorization.

81428436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44381 (or 44373 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 81428436 is about 9023.7706087866. The cubic root of 81428436 is about 433.4363839072.

The spelling of 81428436 in words is "eighty-one million, four hundred twenty-eight thousand, four hundred thirty-six".