21020000 has 60 divisors (see below), whose sum is σ = 51761556. Its totient is φ = 8400000.

The previous prime is 21019993. The next prime is 21020011. The reversal of 21020000 is 2012.

It is a Harshad number since it is a multiple of its sum of digits (5).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 19475 + ... + 20525.

Almost surely, 2^21020000 is an apocalyptic number.

21020000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25880778).

21020000 is an abundant number, since it is smaller than the sum of its proper divisors (30741556).

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

21020000 is an equidigital number, since it uses as much as digits as its factorization.

21020000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1081 (or 1058 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 5.

The square root of 21020000 is about 4584.7573545391. The cubic root of 21020000 is about 275.9799747426.

Adding to 21020000 its reverse (2012), we get a palindrome (21022012).

The spelling of 21020000 in words is "twenty-one million, twenty thousand".