72436021 has 4 divisors (see below), whose sum is σ = 82784032. Its totient is φ = 62088012.

The previous prime is 72435991. The next prime is 72436061. The reversal of 72436021 is 12063427.

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 72436021 - 2¹⁷ = 72304949 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 (72436061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5173995 + ... + 5174008.

It is an arithmetic number, because the mean of its divisors is an integer number (20696008).

Almost surely, 2^72436021 is an apocalyptic number.

It is an amenable number.

72436021 is a deficient number, since it is larger than the sum of its proper divisors (10348011).

72436021 is a wasteful number, since it uses less digits than its factorization.

72436021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10348010.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 72436021 is about 8510.9353775011. The cubic root of 72436021 is about 416.8548530911.

Adding to 72436021 its reverse (12063427), we get a palindrome (84499448).

The spelling of 72436021 in words is "seventy-two million, four hundred thirty-six thousand, twenty-one".