72107561 has 8 divisors (see below), whose sum is σ = 75864264. Its totient is φ = 68446080.

The previous prime is 72107513. The next prime is 72107573. The reversal of 72107561 is 16570127.

It can be written as a sum of positive squares in 4 ways, for example, as 31147561 + 40960000 = 5581^2 + 6400^2 .

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 72107561 - 2²² = 67913257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72109561) 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, 22250 + ... + 25283.

It is an arithmetic number, because the mean of its divisors is an integer number (9483033).

Almost surely, 2^72107561 is an apocalyptic number.

It is an amenable number.

72107561 is a deficient number, since it is larger than the sum of its proper divisors (3756703).

72107561 is a wasteful number, since it uses less digits than its factorization.

72107561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47611.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 72107561 is about 8491.6171015891. The cubic root of 72107561 is about 416.2238244023.

Adding to 72107561 its reverse (16570127), we get a palindrome (88677688).

The spelling of 72107561 in words is "seventy-two million, one hundred seven thousand, five hundred sixty-one".