21053004 has 96 divisors (see below), whose sum is σ = 62125056. Its totient is φ = 5406720.

The previous prime is 21052979. The next prime is 21053009. The reversal of 21053004 is 40035012.

It is not an unprimeable number, because it can be changed into a prime (21053009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 32524 + ... + 33164.

It is an arithmetic number, because the mean of its divisors is an integer number (647136).

Almost surely, 2^21053004 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21053004, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31062528).

21053004 is an abundant number, since it is smaller than the sum of its proper divisors (41072052).

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

21053004 is a wasteful number, since it uses less digits than its factorization.

21053004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695 (or 693 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 21053004 is about 4588.3552608751. The cubic root of 21053004 is about 276.1243401107.

Adding to 21053004 its reverse (40035012), we get a palindrome (61088016).

The spelling of 21053004 in words is "twenty-one million, fifty-three thousand, four".