81288620 has 24 divisors (see below), whose sum is σ = 195093024. Its totient is φ = 27870336.

The previous prime is 81288617. The next prime is 81288643. The reversal of 81288620 is 2688218.

It is a Harshad number since it is a multiple of its sum of digits (35).

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, 290177 + ... + 290456.

It is an arithmetic number, because the mean of its divisors is an integer number (8128876).

Almost surely, 2^81288620 is an apocalyptic number.

It is an amenable number.

81288620 is an abundant number, since it is smaller than the sum of its proper divisors (113804404).

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

81288620 is a wasteful number, since it uses less digits than its factorization.

81288620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 580649 (or 580647 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 35.

The square root of 81288620 is about 9016.0201863128. The cubic root of 81288620 is about 433.1881657066.

The spelling of 81288620 in words is "eighty-one million, two hundred eighty-eight thousand, six hundred twenty".