21020884 has 24 divisors (see below), whose sum is σ = 38045448. Its totient is φ = 10154880.

The previous prime is 21020863. The next prime is 21020893. The reversal of 21020884 is 48802012.

It can be written as a sum of positive squares in 4 ways, for example, as 9610000 + 11410884 = 3100^2 + 3378^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25194 + ... + 26014.

It is an arithmetic number, because the mean of its divisors is an integer number (1585227).

Almost surely, 2^21020884 is an apocalyptic number.

It is an amenable number.

21020884 is a deficient number, since it is larger than the sum of its proper divisors (17024564).

21020884 is a wasteful number, since it uses less digits than its factorization.

21020884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1035 (or 1033 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 21020884 is about 4584.8537599361. The cubic root of 21020884 is about 275.9838434847.

Adding to 21020884 its reverse (48802012), we get a palindrome (69822896).

It can be divided in two parts, 21020 and 884, that added together give a square (21904 = 148²).

The spelling of 21020884 in words is "twenty-one million, twenty thousand, eight hundred eighty-four".