28939851505 has 4 divisors (see below), whose sum is σ = 34727821812. Its totient is φ = 23151881200.

The previous prime is 28939851503. The next prime is 28939851527. The reversal of 28939851505 is 50515893982.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50515893982 = 2 ⋅25257946991.

It can be written as a sum of positive squares in 2 ways, for example, as 16867775376 + 12072076129 = 129876^2 + 109873^2 .

It is not a de Polignac number, because 28939851505 - 2¹ = 28939851503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28939851503) 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, 2893985146 + ... + 2893985155.

It is an arithmetic number, because the mean of its divisors is an integer number (8681955453).

Almost surely, 2^28939851505 is an apocalyptic number.

It is an amenable number.

28939851505 is a deficient number, since it is larger than the sum of its proper divisors (5787970307).

28939851505 is an equidigital number, since it uses as much as digits as its factorization.

28939851505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5787970306.

The product of its (nonzero) digits is 3888000, while the sum is 55.

The spelling of 28939851505 in words is "twenty-eight billion, nine hundred thirty-nine million, eight hundred fifty-one thousand, five hundred five".