21026020 has 12 divisors (see below), whose sum is σ = 44154684. Its totient is φ = 8410400.

The previous prime is 21025987. The next prime is 21026053. The reversal of 21026020 is 2062012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21025987) and next prime (21026053).

It can be written as a sum of positive squares in 2 ways, for example, as 16386304 + 4639716 = 4048^2 + 2154^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525631 + ... + 525670.

It is an arithmetic number, because the mean of its divisors is an integer number (3679557).

Almost surely, 2^21026020 is an apocalyptic number.

21026020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21026020 is an abundant number, since it is smaller than the sum of its proper divisors (23128664).

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

21026020 is a wasteful number, since it uses less digits than its factorization.

21026020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051310 (or 1051308 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21026020 is about 4585.4138308336. The cubic root of 21026020 is about 276.0063185559.

Adding to 21026020 its reverse (2062012), we get a palindrome (23088032).

The spelling of 21026020 in words is "twenty-one million, twenty-six thousand, twenty".