72735561 has 12 divisors (see below), whose sum is σ = 105332292. Its totient is φ = 48365856.

The previous prime is 72735541. The next prime is 72735569. The reversal of 72735561 is 16553727.

It can be written as a sum of positive squares in 2 ways, for example, as 45643536 + 27092025 = 6756^2 + 5205^2 .

It is not a de Polignac number, because 72735561 - 2⁷ = 72735433 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72735569) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6606 + ... + 13751.

It is an arithmetic number, because the mean of its divisors is an integer number (8777691).

Almost surely, 2^72735561 is an apocalyptic number.

It is an amenable number.

72735561 is a deficient number, since it is larger than the sum of its proper divisors (32596731).

72735561 is a wasteful number, since it uses less digits than its factorization.

72735561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20760 (or 20757 counting only the distinct ones).

The product of its digits is 44100, while the sum is 36.

The square root of 72735561 is about 8528.5145834430. The cubic root of 72735561 is about 417.4286605252.

The spelling of 72735561 in words is "seventy-two million, seven hundred thirty-five thousand, five hundred sixty-one".