72503521 has 16 divisors (see below), whose sum is σ = 80901504. Its totient is φ = 64624384.

The previous prime is 72503503. The next prime is 72503531. The reversal of 72503521 is 12530527.

It is a cyclic number.

It is not a de Polignac number, because 72503521 - 2⁵ = 72503489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (72503531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40971 + ... + 42703.

It is an arithmetic number, because the mean of its divisors is an integer number (5056344).

Almost surely, 2^72503521 is an apocalyptic number.

It is an amenable number.

72503521 is a deficient number, since it is larger than the sum of its proper divisors (8397983).

72503521 is a wasteful number, since it uses less digits than its factorization.

72503521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1880.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 72503521 is about 8514.8999406922. The cubic root of 72503521 is about 416.9842959043.

The spelling of 72503521 in words is "seventy-two million, five hundred three thousand, five hundred twenty-one".