81028023857 has 16 divisors (see below), whose sum is σ = 93099497472. Its totient is φ = 69800631120.

The previous prime is 81028023787. The next prime is 81028023859. The reversal of 81028023857 is 75832082018.

It is not a de Polignac number, because 81028023857 - 2²⁸ = 80759588401 is a prime.

It is a super-2 number, since 2×81028023857² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81028023859) 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, 1469513 + ... + 1523654.

It is an arithmetic number, because the mean of its divisors is an integer number (5818718592).

Almost surely, 2^81028023857 is an apocalyptic number.

It is an amenable number.

81028023857 is a deficient number, since it is larger than the sum of its proper divisors (12071473615).

81028023857 is a wasteful number, since it uses less digits than its factorization.

81028023857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2993308.

The product of its (nonzero) digits is 215040, while the sum is 44.

The spelling of 81028023857 in words is "eighty-one billion, twenty-eight million, twenty-three thousand, eight hundred fifty-seven".