28021779 has 6 divisors (see below), whose sum is σ = 40475916. Its totient is φ = 18681180.

The previous prime is 28021771. The next prime is 28021781. The reversal of 28021779 is 97712082.

It is not a de Polignac number, because 28021779 - 2³ = 28021771 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28021771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1556757 + ... + 1556774.

It is an arithmetic number, because the mean of its divisors is an integer number (6745986).

Almost surely, 2^28021779 is an apocalyptic number.

28021779 is a deficient number, since it is larger than the sum of its proper divisors (12454137).

28021779 is a wasteful number, since it uses less digits than its factorization.

28021779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3113537 (or 3113534 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 28021779 is about 5293.5601441752. The cubic root of 28021779 is about 303.7376075826.

The spelling of 28021779 in words is "twenty-eight million, twenty-one thousand, seven hundred seventy-nine".