28639901 has 4 divisors (see below), whose sum is σ = 28655712. Its totient is φ = 28624092.

The previous prime is 28639847. The next prime is 28639913. The reversal of 28639901 is 10993682.

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.

It is a cyclic number.

It is not a de Polignac number, because 28639901 - 2¹⁸ = 28377757 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 (28639931) 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, 4775 + ... + 8948.

It is an arithmetic number, because the mean of its divisors is an integer number (7163928).

Almost surely, 2^28639901 is an apocalyptic number.

It is an amenable number.

28639901 is a deficient number, since it is larger than the sum of its proper divisors (15811).

28639901 is a wasteful number, since it uses less digits than its factorization.

28639901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15810.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 28639901 is about 5351.6260145866. The cubic root of 28639901 is about 305.9547293730.

The spelling of 28639901 in words is "twenty-eight million, six hundred thirty-nine thousand, nine hundred one".