21035620 has 12 divisors (see below), whose sum is σ = 44174844. Its totient is φ = 8414240.

The previous prime is 21035617. The next prime is 21035621. The reversal of 21035620 is 2653012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16257024 + 4778596 = 4032^2 + 2186^2 .

It is not an unprimeable number, because it can be changed into a prime (21035621) 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 3 ways as a sum of consecutive naturals, for example, 525871 + ... + 525910.

It is an arithmetic number, because the mean of its divisors is an integer number (3681237).

Almost surely, 2^21035620 is an apocalyptic number.

21035620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21035620 is an abundant number, since it is smaller than the sum of its proper divisors (23139224).

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

21035620 is a wasteful number, since it uses less digits than its factorization.

21035620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051790 (or 1051788 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21035620 is about 4586.4605089328. The cubic root of 21035620 is about 276.0483182227.

Adding to 21035620 its reverse (2653012), we get a palindrome (23688632).

The spelling of 21035620 in words is "twenty-one million, thirty-five thousand, six hundred twenty".