28108869649 has 27 divisors (see below), whose sum is σ = 33536386107. Its totient is φ = 23490757584.

The previous prime is 28108869619. The next prime is 28108869653. The reversal of 28108869649 is 94696880182.

The square root of 28108869649 is 167657.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 2466612225 + 25642257424 = 49665^2 + 160132^2 .

It is not a de Polignac number, because 28108869649 - 2²¹ = 28106772497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28108869619) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 50464479 + ... + 50465035.

Almost surely, 2^28108869649 is an apocalyptic number.

28108869649 is the 167657-th square number.

28108869649 is the 83829-th centered octagonal number.

It is an amenable number.

28108869649 is a deficient number, since it is larger than the sum of its proper divisors (5427516458).

28108869649 is an frugal number, since it uses more digits than its factorization.

28108869649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1214 (or 607 counting only the distinct ones).

The product of its (nonzero) digits is 11943936, while the sum is 61.

The spelling of 28108869649 in words is "twenty-eight billion, one hundred eight million, eight hundred sixty-nine thousand, six hundred forty-nine".