72518581 has 4 divisors (see below), whose sum is σ = 72952992. Its totient is φ = 72084172.

The previous prime is 72518561. The next prime is 72518591. The reversal of 72518581 is 18581527.

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 72518581 - 2¹⁵ = 72485813 is a prime.

It is a super-2 number, since 2×72518581² = 10517889180507122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72518581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72518521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 216955 + ... + 217288.

It is an arithmetic number, because the mean of its divisors is an integer number (18238248).

Almost surely, 2^72518581 is an apocalyptic number.

It is an amenable number.

72518581 is a deficient number, since it is larger than the sum of its proper divisors (434411).

72518581 is a wasteful number, since it uses less digits than its factorization.

72518581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434410.

The product of its digits is 22400, while the sum is 37.

The square root of 72518581 is about 8515.7842269517. The cubic root of 72518581 is about 417.0131650712.

It can be divided in two parts, 725 and 18581, that added together give a triangular number (19306 = T₁₉₆).

The spelling of 72518581 in words is "seventy-two million, five hundred eighteen thousand, five hundred eighty-one".