81019428 has 24 divisors (see below), whose sum is σ = 216052032. Its totient is φ = 23148384.

The previous prime is 81019397. The next prime is 81019429. The reversal of 81019428 is 82491018.

It is not an unprimeable number, because it can be changed into a prime (81019429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 482175 + ... + 482342.

It is an arithmetic number, because the mean of its divisors is an integer number (9002168).

Almost surely, 2^81019428 is an apocalyptic number.

It is an amenable number.

81019428 is an abundant number, since it is smaller than the sum of its proper divisors (135032604).

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

81019428 is a wasteful number, since it uses less digits than its factorization.

81019428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 964531 (or 964529 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 81019428 is about 9001.0792686211. The cubic root of 81019428 is about 432.7094609499.

The spelling of 81019428 in words is "eighty-one million, nineteen thousand, four hundred twenty-eight".