72143921 has 4 divisors (see below), whose sum is σ = 72210432. Its totient is φ = 72077412.

The previous prime is 72143899. The next prime is 72143933. The reversal of 72143921 is 12934127.

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 72143921 - 2¹⁴ = 72127537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72143321) 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, 31601 + ... + 33806.

It is an arithmetic number, because the mean of its divisors is an integer number (18052608).

Almost surely, 2^72143921 is an apocalyptic number.

It is an amenable number.

72143921 is a deficient number, since it is larger than the sum of its proper divisors (66511).

72143921 is a wasteful number, since it uses less digits than its factorization.

72143921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66510.

The product of its digits is 3024, while the sum is 29.

The square root of 72143921 is about 8493.7577667367. The cubic root of 72143921 is about 416.2937724771.

The spelling of 72143921 in words is "seventy-two million, one hundred forty-three thousand, nine hundred twenty-one".