72107521 has 4 divisors (see below), whose sum is σ = 72140544. Its totient is φ = 72074500.

The previous prime is 72107513. The next prime is 72107573. The reversal of 72107521 is 12570127.

It is a happy number.

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 72107521 - 2³ = 72107513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72107821) 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, 12985 + ... + 17686.

It is an arithmetic number, because the mean of its divisors is an integer number (18035136).

Almost surely, 2^72107521 is an apocalyptic number.

It is an amenable number.

72107521 is a deficient number, since it is larger than the sum of its proper divisors (33023).

72107521 is a wasteful number, since it uses less digits than its factorization.

72107521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33022.

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 72107521 is about 8491.6147463248. The cubic root of 72107521 is about 416.2237474387.

Adding to 72107521 its reverse (12570127), we get a palindrome (84677648).

The spelling of 72107521 in words is "seventy-two million, one hundred seven thousand, five hundred twenty-one".