28309990 has 16 divisors (see below), whose sum is σ = 51064848. Its totient is φ = 11300256.

The previous prime is 28309949. The next prime is 28309999. The reversal of 28309990 is 9990382.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28309999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2524 + ... + 7936.

It is an arithmetic number, because the mean of its divisors is an integer number (3191553).

Almost surely, 2^28309990 is an apocalyptic number.

28309990 is a deficient number, since it is larger than the sum of its proper divisors (22754858).

28309990 is a wasteful number, since it uses less digits than its factorization.

28309990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5943.

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 28309990 is about 5320.7132980457. The cubic root of 28309990 is about 304.7753967667.

The spelling of 28309990 in words is "twenty-eight million, three hundred nine thousand, nine hundred ninety".