81428040 has 48 divisors (see below), whose sum is σ = 264642300. Its totient is φ = 21714048.

The previous prime is 81428029. The next prime is 81428057. The reversal of 81428040 is 4082418.

It can be written as a sum of positive squares in 2 ways, for example, as 80030916 + 1397124 = 8946^2 + 1182^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81427995 and 81428013.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 112735 + ... + 113454.

Almost surely, 2^81428040 is an apocalyptic number.

It is an amenable number.

81428040 is an abundant number, since it is smaller than the sum of its proper divisors (183214260).

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

81428040 is a wasteful number, since it uses less digits than its factorization.

81428040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226206 (or 226199 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 81428040 is about 9023.7486667127. The cubic root of 81428040 is about 433.4356812817.

The spelling of 81428040 in words is "eighty-one million, four hundred twenty-eight thousand, forty".