21051884 has 12 divisors (see below), whose sum is σ = 42103824. Its totient is φ = 9022224.

The previous prime is 21051859. The next prime is 21051887. The reversal of 21051884 is 48815012.

21051884 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21051887) 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, 375899 + ... + 375954.

It is an arithmetic number, because the mean of its divisors is an integer number (3508652).

Almost surely, 2^21051884 is an apocalyptic number.

It is an amenable number.

21051884 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21051884 is a wasteful number, since it uses less digits than its factorization.

21051884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751864 (or 751862 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 21051884 is about 4588.2332111609. The cubic root of 21051884 is about 276.1194435055.

Adding to 21051884 its reverse (48815012), we get a palindrome (69866896).

The spelling of 21051884 in words is "twenty-one million, fifty-one thousand, eight hundred eighty-four".