81428906893 has 8 divisors (see below), whose sum is σ = 82787141016. Its totient is φ = 80071425600.

The previous prime is 81428906813. The next prime is 81428906929. The reversal of 81428906893 is 39860982418.

It can be written as a sum of positive squares in 4 ways, for example, as 289444 + 81428617449 = 538^2 + 285357^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81428906893 - 2²¹ = 81426809741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81428906813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32055 + ... + 404827.

It is an arithmetic number, because the mean of its divisors is an integer number (10348392627).

Almost surely, 2^81428906893 is an apocalyptic number.

It is an amenable number.

81428906893 is a deficient number, since it is larger than the sum of its proper divisors (1358234123).

81428906893 is a wasteful number, since it uses less digits than its factorization.

81428906893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376415.

The product of its (nonzero) digits is 5971968, while the sum is 58.

The spelling of 81428906893 in words is "eighty-one billion, four hundred twenty-eight million, nine hundred six thousand, eight hundred ninety-three".