81366428 has 48 divisors (see below), whose sum is σ = 170190720. Its totient is φ = 33547200.

The previous prime is 81366421. The next prime is 81366443. The reversal of 81366428 is 82466318.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81366391 and 81366400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81366421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32543 + ... + 34953.

It is an arithmetic number, because the mean of its divisors is an integer number (3545640).

Almost surely, 2^81366428 is an apocalyptic number.

It is an amenable number.

81366428 is an abundant number, since it is smaller than the sum of its proper divisors (88824292).

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

81366428 is a wasteful number, since it uses less digits than its factorization.

81366428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2498 (or 2496 counting only the distinct ones).

The product of its digits is 55296, while the sum is 38.

The square root of 81366428 is about 9020.3341401525. The cubic root of 81366428 is about 433.3263349297.

The spelling of 81366428 in words is "eighty-one million, three hundred sixty-six thousand, four hundred twenty-eight".