28390807 has 4 divisors (see below), whose sum is σ = 29885080. Its totient is φ = 26896536.

The previous prime is 28390787. The next prime is 28390811. The reversal of 28390807 is 70809382.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28390807 is a prime.

It is a super-2 number, since 2×28390807² = 1612075844222498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28390207) 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, 747108 + ... + 747145.

It is an arithmetic number, because the mean of its divisors is an integer number (7471270).

Almost surely, 2^28390807 is an apocalyptic number.

28390807 is a deficient number, since it is larger than the sum of its proper divisors (1494273).

28390807 is a wasteful number, since it uses less digits than its factorization.

28390807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1494272.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 28390807 is about 5328.3024501242. The cubic root of 28390807 is about 305.0651370332.

The spelling of 28390807 in words is "twenty-eight million, three hundred ninety thousand, eight hundred seven".