72261621 has 6 divisors (see below), whose sum is σ = 104377910. Its totient is φ = 48174408.

The previous prime is 72261593. The next prime is 72261643. The reversal of 72261621 is 12616227.

72261621 is a `hidden beast` number, since 7 + 22 + 616 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 60606225 + 11655396 = 7785^2 + 3414^2 .

It is not a de Polignac number, because 72261621 - 2⁷ = 72261493 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72261661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4014526 + ... + 4014543.

Almost surely, 2^72261621 is an apocalyptic number.

It is an amenable number.

72261621 is a deficient number, since it is larger than the sum of its proper divisors (32116289).

72261621 is a wasteful number, since it uses less digits than its factorization.

72261621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8029075 (or 8029072 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 72261621 is about 8500.6835607497. The cubic root of 72261621 is about 416.5200385043.

Adding to 72261621 its reverse (12616227), we get a palindrome (84877848).

The spelling of 72261621 in words is "seventy-two million, two hundred sixty-one thousand, six hundred twenty-one".