72021 has 4 divisors (see below), whose sum is σ = 96032. Its totient is φ = 48012.

The previous prime is 72019. The next prime is 72031. The reversal of 72021 is 12027.

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 not a de Polignac number, because 72021 - 2¹ = 72019 is a prime.

It is a D-number.

It is a Duffinian number.

72021 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 71988 and 72006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72031) 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, 12001 + ... + 12006.

It is an arithmetic number, because the mean of its divisors is an integer number (24008).

2⁷²⁰²¹ is an apocalyptic number.

It is an amenable number.

72021 is a deficient number, since it is larger than the sum of its proper divisors (24011).

72021 is a wasteful number, since it uses less digits than its factorization.

72021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24010.

The product of its (nonzero) digits is 28, while the sum is 12.

The square root of 72021 is about 268.3672856367. The cubic root of 72021 is about 41.6057206753.

Adding to 72021 its reverse (12027), we get a palindrome (84048).

It can be divided in two parts, 720 and 21, that added together give a triangular number (741 = T₃₈).

The spelling of 72021 in words is "seventy-two thousand, twenty-one", and thus it is an iban number.