28215539 has 4 divisors (see below), whose sum is σ = 30780600. Its totient is φ = 25650480.

The previous prime is 28215527. The next prime is 28215541. The reversal of 28215539 is 93551282.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28215539 - 2⁸ = 28215283 is a prime.

It is a super-2 number, since 2×28215539² = 1592233282121042, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28215499 and 28215508.

It is not an unprimeable number, because it can be changed into a prime (28215559) 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, 1282514 + ... + 1282535.

It is an arithmetic number, because the mean of its divisors is an integer number (7695150).

Almost surely, 2^28215539 is an apocalyptic number.

28215539 is a deficient number, since it is larger than the sum of its proper divisors (2565061).

28215539 is a wasteful number, since it uses less digits than its factorization.

28215539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2565060.

The product of its digits is 21600, while the sum is 35.

The square root of 28215539 is about 5311.8300989395. The cubic root of 28215539 is about 304.4360770438.

The spelling of 28215539 in words is "twenty-eight million, two hundred fifteen thousand, five hundred thirty-nine".