28951909 has 4 divisors (see below), whose sum is σ = 33087904. Its totient is φ = 24815916.

The previous prime is 28951907. The next prime is 28951919. The reversal of 28951909 is 90915982.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90915982 = 2 ⋅45457991.

It is a cyclic number.

It is not a de Polignac number, because 28951909 - 2¹ = 28951907 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 (28951903) 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, 2067987 + ... + 2068000.

It is an arithmetic number, because the mean of its divisors is an integer number (8271976).

Almost surely, 2^28951909 is an apocalyptic number.

It is an amenable number.

28951909 is a deficient number, since it is larger than the sum of its proper divisors (4135995).

28951909 is an equidigital number, since it uses as much as digits as its factorization.

28951909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4135994.

The product of its (nonzero) digits is 58320, while the sum is 43.

The square root of 28951909 is about 5380.6978171981. The cubic root of 28951909 is about 307.0617601134.

The spelling of 28951909 in words is "twenty-eight million, nine hundred fifty-one thousand, nine hundred nine".