28920513 has 4 divisors (see below), whose sum is σ = 38560688. Its totient is φ = 19280340.

The previous prime is 28920509. The next prime is 28920517. The reversal of 28920513 is 31502982.

It is a happy number.

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.

It is an interprime number because it is at equal distance from previous prime (28920509) and next prime (28920517).

It is not a de Polignac number, because 28920513 - 2² = 28920509 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28920517) 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, 4820083 + ... + 4820088.

It is an arithmetic number, because the mean of its divisors is an integer number (9640172).

Almost surely, 2^28920513 is an apocalyptic number.

It is an amenable number.

28920513 is a deficient number, since it is larger than the sum of its proper divisors (9640175).

28920513 is an equidigital number, since it uses as much as digits as its factorization.

28920513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9640174.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 28920513 is about 5377.7795603762. The cubic root of 28920513 is about 306.9507254328.

It can be divided in two parts, 289 and 20513, that added together give a palindrome (20802).

The spelling of 28920513 in words is "twenty-eight million, nine hundred twenty thousand, five hundred thirteen".