28400207 has 4 divisors (see below), whose sum is σ = 30982056. Its totient is φ = 25818360.

The previous prime is 28400159. The next prime is 28400219. The reversal of 28400207 is 70200482.

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 28400207 - 2¹⁶ = 28334671 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28400257) 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, 1290908 + ... + 1290929.

It is an arithmetic number, because the mean of its divisors is an integer number (7745514).

Almost surely, 2^28400207 is an apocalyptic number.

28400207 is a deficient number, since it is larger than the sum of its proper divisors (2581849).

28400207 is a wasteful number, since it uses less digits than its factorization.

28400207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2581848.

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 28400207 is about 5329.1844591832. The cubic root of 28400207 is about 305.0988016376.

Adding to 28400207 its reverse (70200482), we get a palindrome (98600689).

The spelling of 28400207 in words is "twenty-eight million, four hundred thousand, two hundred seven".