28212901 has 4 divisors (see below), whose sum is σ = 28233772. Its totient is φ = 28192032.

The previous prime is 28212893. The next prime is 28212913. The reversal of 28212901 is 10921282.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12602500 + 15610401 = 3550^2 + 3951^2 .

It is a cyclic number.

It is not a de Polignac number, because 28212901 - 2³ = 28212893 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 (28212941) 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, 8256 + ... + 11161.

It is an arithmetic number, because the mean of its divisors is an integer number (7058443).

Almost surely, 2^28212901 is an apocalyptic number.

It is an amenable number.

28212901 is a deficient number, since it is larger than the sum of its proper divisors (20871).

28212901 is a wasteful number, since it uses less digits than its factorization.

28212901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20870.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 28212901 is about 5311.5817794702. The cubic root of 28212901 is about 304.4265890403.

The spelling of 28212901 in words is "twenty-eight million, two hundred twelve thousand, nine hundred one".