72545447581 has 8 divisors (see below), whose sum is σ = 72602389944. Its totient is φ = 72488532480.

The previous prime is 72545447561. The next prime is 72545447587. The reversal of 72545447581 is 18574454527.

It can be written as a sum of positive squares in 4 ways, for example, as 46401468100 + 26143979481 = 215410^2 + 161691^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 72545447581 - 2⁹ = 72545447069 is a prime.

It is a super-2 number, since 2×72545447581² (a number of 23 digits) 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 (72545447587) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10484535 + ... + 10491451.

It is an arithmetic number, because the mean of its divisors is an integer number (9075298743).

Almost surely, 2^72545447581 is an apocalyptic number.

It is an amenable number.

72545447581 is a deficient number, since it is larger than the sum of its proper divisors (56942363).

72545447581 is a wasteful number, since it uses less digits than its factorization.

72545447581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13631.

The product of its digits is 6272000, while the sum is 52.

The spelling of 72545447581 in words is "seventy-two billion, five hundred forty-five million, four hundred forty-seven thousand, five hundred eighty-one".