28312756491 has 4 divisors (see below), whose sum is σ = 37750341992. Its totient is φ = 18875170992.

The previous prime is 28312756487. The next prime is 28312756529. The reversal of 28312756491 is 19465721382.

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

It is not a de Polignac number, because 28312756491 - 2² = 28312756487 is a prime.

It is a super-2 number, since 2×28312756491² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28312756491.

It is not an unprimeable number, because it can be changed into a prime (28312756411) 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, 4718792746 + ... + 4718792751.

It is an arithmetic number, because the mean of its divisors is an integer number (9437585498).

Almost surely, 2^28312756491 is an apocalyptic number.

28312756491 is a deficient number, since it is larger than the sum of its proper divisors (9437585501).

28312756491 is an equidigital number, since it uses as much as digits as its factorization.

28312756491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9437585500.

The product of its digits is 725760, while the sum is 48.

The spelling of 28312756491 in words is "twenty-eight billion, three hundred twelve million, seven hundred fifty-six thousand, four hundred ninety-one".