21162021 has 4 divisors (see below), whose sum is σ = 28216032. Its totient is φ = 14108012.

The previous prime is 21162019. The next prime is 21162041. The reversal of 21162021 is 12026112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21162021 - 2¹ = 21162019 is a prime.

It is a super-2 number, since 2×21162021² = 895662265608882, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21162041) 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, 3527001 + ... + 3527006.

It is an arithmetic number, because the mean of its divisors is an integer number (7054008).

Almost surely, 2^21162021 is an apocalyptic number.

It is an amenable number.

21162021 is a deficient number, since it is larger than the sum of its proper divisors (7054011).

21162021 is an equidigital number, since it uses as much as digits as its factorization.

21162021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7054010.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 21162021 is about 4600.2196686680. The cubic root of 21162021 is about 276.6001302877.

Adding to 21162021 its reverse (12026112), we get a palindrome (33188133).

The spelling of 21162021 in words is "twenty-one million, one hundred sixty-two thousand, twenty-one".