28406939 has 6 divisors (see below), whose sum is σ = 31008684. Its totient is φ = 25808420.

The previous prime is 28406929. The next prime is 28407011. The reversal of 28406939 is 93960482.

It is a happy number.

It is not a de Polignac number, because 28406939 - 2⁴ = 28406923 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28406896 and 28406905.

It is not an unprimeable number, because it can be changed into a prime (28406929) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16874 + ... + 18480.

It is an arithmetic number, because the mean of its divisors is an integer number (5168114).

Almost surely, 2^28406939 is an apocalyptic number.

28406939 is a deficient number, since it is larger than the sum of its proper divisors (2601745).

28406939 is an frugal number, since it uses more digits than its factorization.

28406939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3225 (or 1618 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 41.

The square root of 28406939 is about 5329.8160381011. The cubic root of 28406939 is about 305.1229066599.

It can be divided in two parts, 2840 and 6939, that added together give a palindrome (9779).

The spelling of 28406939 in words is "twenty-eight million, four hundred six thousand, nine hundred thirty-nine".