81428064 has 48 divisors (see below), whose sum is σ = 218308608. Its totient is φ = 26563712.

The previous prime is 81428057. The next prime is 81428071. The reversal of 81428064 is 46082418.

It is an interprime number because it is at equal distance from previous prime (81428057) and next prime (81428071).

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4512 + ... + 13535.

It is an arithmetic number, because the mean of its divisors is an integer number (4548096).

Almost surely, 2^81428064 is an apocalyptic number.

It is an amenable number.

81428064 is an abundant number, since it is smaller than the sum of its proper divisors (136880544).

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

81428064 is a wasteful number, since it uses less digits than its factorization.

81428064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18107 (or 18099 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 33.

The square root of 81428064 is about 9023.7499965369. The cubic root of 81428064 is about 433.4357238651.

The spelling of 81428064 in words is "eighty-one million, four hundred twenty-eight thousand, sixty-four".