21362021 has 4 divisors (see below), whose sum is σ = 21765132. Its totient is φ = 20958912.

The previous prime is 21361957. The next prime is 21362041. The reversal of 21362021 is 12026312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12888100 + 8473921 = 3590^2 + 2911^2 .

It is a cyclic number.

It is not a de Polignac number, because 21362021 - 2⁶ = 21361957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21362041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201476 + ... + 201581.

It is an arithmetic number, because the mean of its divisors is an integer number (5441283).

Almost surely, 2^21362021 is an apocalyptic number.

It is an amenable number.

21362021 is a deficient number, since it is larger than the sum of its proper divisors (403111).

21362021 is an equidigital number, since it uses as much as digits as its factorization.

21362021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403110.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21362021 is about 4621.9066412034. The cubic root of 21362021 is about 277.4687722888.

Adding to 21362021 its reverse (12026312), we get a palindrome (33388333).

The spelling of 21362021 in words is "twenty-one million, three hundred sixty-two thousand, twenty-one".