28139513 has 4 divisors (see below), whose sum is σ = 29620560. Its totient is φ = 26658468.

The previous prime is 28139491. The next prime is 28139533. The reversal of 28139513 is 31593182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31593182 = 2 ⋅15796591.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28139513 is a prime.

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 28139513.

It is not an unprimeable number, because it can be changed into a prime (28139533) 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, 740495 + ... + 740532.

It is an arithmetic number, because the mean of its divisors is an integer number (7405140).

Almost surely, 2^28139513 is an apocalyptic number.

It is an amenable number.

28139513 is a deficient number, since it is larger than the sum of its proper divisors (1481047).

28139513 is a wasteful number, since it uses less digits than its factorization.

28139513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481046.

The product of its digits is 6480, while the sum is 32.

The square root of 28139513 is about 5304.6689811901. The cubic root of 28139513 is about 304.1623995231.

The spelling of 28139513 in words is "twenty-eight million, one hundred thirty-nine thousand, five hundred thirteen".