2172036021 has 4 divisors (see below), whose sum is σ = 2896048032. Its totient is φ = 1448024012.

The previous prime is 2172036017. The next prime is 2172036023. The reversal of 2172036021 is 1206302712.

2172036021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2172036021 - 2² = 2172036017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2172035982 and 2172036000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2172036023) 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, 362006001 + ... + 362006006.

It is an arithmetic number, because the mean of its divisors is an integer number (724012008).

Almost surely, 2^2172036021 is an apocalyptic number.

It is an amenable number.

2172036021 is a deficient number, since it is larger than the sum of its proper divisors (724012011).

2172036021 is an equidigital number, since it uses as much as digits as its factorization.

2172036021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724012010.

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 2172036021 is about 46605.1072415889. The cubic root of 2172036021 is about 1295.0573700875.

Adding to 2172036021 its reverse (1206302712), we get a palindrome (3378338733).

The spelling of 2172036021 in words is "two billion, one hundred seventy-two million, thirty-six thousand, twenty-one".