81428811 has 4 divisors (see below), whose sum is σ = 108571752. Its totient is φ = 54285872.

The previous prime is 81428807. The next prime is 81428821. The reversal of 81428811 is 11882418.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81428811 - 2² = 81428807 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81428801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13571466 + ... + 13571471.

It is an arithmetic number, because the mean of its divisors is an integer number (27142938).

Almost surely, 2^81428811 is an apocalyptic number.

81428811 is a deficient number, since it is larger than the sum of its proper divisors (27142941).

81428811 is a wasteful number, since it uses less digits than its factorization.

81428811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27142940.

The product of its digits is 4096, while the sum is 33.

The square root of 81428811 is about 9023.7913872164. The cubic root of 81428811 is about 433.4370492702.

The spelling of 81428811 in words is "eighty-one million, four hundred twenty-eight thousand, eight hundred eleven".