20821868 has 6 divisors (see below), whose sum is σ = 36438276. Its totient is φ = 10410932.

The previous prime is 20821849. The next prime is 20821873. The reversal of 20821868 is 86812802.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2602730 + ... + 2602737.

It is an arithmetic number, because the mean of its divisors is an integer number (6073046).

Almost surely, 2^20821868 is an apocalyptic number.

It is an amenable number.

20821868 is a deficient number, since it is larger than the sum of its proper divisors (15616408).

20821868 is a wasteful number, since it uses less digits than its factorization.

20821868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5205471 (or 5205469 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 35.

The square root of 20821868 is about 4563.0985086890. The cubic root of 20821868 is about 275.1101178832.

The spelling of 20821868 in words is "twenty million, eight hundred twenty-one thousand, eight hundred sixty-eight".