28931370857 has 4 divisors (see below), whose sum is σ = 29003519316. Its totient is φ = 28859222400.

The previous prime is 28931370821. The next prime is 28931370863. The reversal of 28931370857 is 75807313982.

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

It can be written as a sum of positive squares in 2 ways, for example, as 20806331536 + 8125039321 = 144244^2 + 90139^2 .

It is a cyclic number.

It is not a de Polignac number, because 28931370857 - 2¹⁰ = 28931369833 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28931370799 and 28931370808.

It is not an unprimeable number, because it can be changed into a prime (28931370557) 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, 36073628 + ... + 36074429.

It is an arithmetic number, because the mean of its divisors is an integer number (7250879829).

Almost surely, 2^28931370857 is an apocalyptic number.

It is an amenable number.

28931370857 is a deficient number, since it is larger than the sum of its proper divisors (72148459).

28931370857 is an equidigital number, since it uses as much as digits as its factorization.

28931370857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72148458.

The product of its (nonzero) digits is 2540160, while the sum is 53.

The spelling of 28931370857 in words is "twenty-eight billion, nine hundred thirty-one million, three hundred seventy thousand, eight hundred fifty-seven".