72447581 has 4 divisors (see below), whose sum is σ = 72596832. Its totient is φ = 72298332.

The previous prime is 72447559. The next prime is 72447601. The reversal of 72447581 is 18574427.

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 72447581 - 2¹⁰ = 72446557 is a prime.

It is a super-2 number, since 2×72447581² = 10497303985503122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72447511) 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, 73895 + ... + 74868.

It is an arithmetic number, because the mean of its divisors is an integer number (18149208).

Almost surely, 2^72447581 is an apocalyptic number.

It is an amenable number.

72447581 is a deficient number, since it is larger than the sum of its proper divisors (149251).

72447581 is a wasteful number, since it uses less digits than its factorization.

72447581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149250.

The product of its digits is 62720, while the sum is 38.

The square root of 72447581 is about 8511.6144767018. The cubic root of 72447581 is about 416.8770270763.

The spelling of 72447581 in words is "seventy-two million, four hundred forty-seven thousand, five hundred eighty-one".