28207979749 has 4 divisors (see below), whose sum is σ = 28740205836. Its totient is φ = 27675753664.

The previous prime is 28207979731. The next prime is 28207979771. The reversal of 28207979749 is 94797970282.

It is a happy number.

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 13045751524 + 15162228225 = 114218^2 + 123135^2 .

It is a cyclic number.

It is not a de Polignac number, because 28207979749 - 2¹¹ = 28207977701 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 (28207979729) 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, 266112964 + ... + 266113069.

It is an arithmetic number, because the mean of its divisors is an integer number (7185051459).

Almost surely, 2^28207979749 is an apocalyptic number.

It is an amenable number.

28207979749 is a deficient number, since it is larger than the sum of its proper divisors (532226087).

28207979749 is an equidigital number, since it uses as much as digits as its factorization.

28207979749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 532226086.

The product of its (nonzero) digits is 32006016, while the sum is 64.

The spelling of 28207979749 in words is "twenty-eight billion, two hundred seven million, nine hundred seventy-nine thousand, seven hundred forty-nine".