28877821 has 4 divisors (see below), whose sum is σ = 33003232. Its totient is φ = 24752412.

The previous prime is 28877809. The next prime is 28877843. The reversal of 28877821 is 12877882.

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 28877821 - 2⁹ = 28877309 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 (28877861) 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, 2062695 + ... + 2062708.

It is an arithmetic number, because the mean of its divisors is an integer number (8250808).

Almost surely, 2^28877821 is an apocalyptic number.

It is an amenable number.

28877821 is a deficient number, since it is larger than the sum of its proper divisors (4125411).

28877821 is an equidigital number, since it uses as much as digits as its factorization.

28877821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4125410.

The product of its digits is 100352, while the sum is 43.

The square root of 28877821 is about 5373.8087982361. The cubic root of 28877821 is about 306.7996124632.

The spelling of 28877821 in words is "twenty-eight million, eight hundred seventy-seven thousand, eight hundred twenty-one".