21020814 has 12 divisors (see below), whose sum is σ = 45545136. Its totient is φ = 7006932.

The previous prime is 21020803. The next prime is 21020819. The reversal of 21020814 is 41802012.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1167823 = 21020814 / (2 + 1 + 0 + 2 + 0 + 8 + 1 + 4).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020819) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 583894 + ... + 583929.

It is an arithmetic number, because the mean of its divisors is an integer number (3795428).

Almost surely, 2^21020814 is an apocalyptic number.

21020814 is an abundant number, since it is smaller than the sum of its proper divisors (24524322).

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

21020814 is a wasteful number, since it uses less digits than its factorization.

21020814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167831 (or 1167828 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 21020814 is about 4584.8461260985. The cubic root of 21020814 is about 275.9835371403.

Adding to 21020814 its reverse (41802012), we get a palindrome (62822826).

The spelling of 21020814 in words is "twenty-one million, twenty thousand, eight hundred fourteen".