72155620605221 has 8 divisors (see below), whose sum is σ = 72558381688440. Its totient is φ = 71753883058368.

The previous prime is 72155620605191. The next prime is 72155620605241. The reversal of 72155620605221 is 12250602655127.

It can be written as a sum of positive squares in 4 ways, for example, as 6295010748196 + 65860609857025 = 2508986^2 + 8115455^2 .

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 72155620605221 - 2¹⁴ = 72155620588837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72155620605241) 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 7 ways as a sum of consecutive naturals, for example, 255742706 + ... + 256024691.

It is an arithmetic number, because the mean of its divisors is an integer number (9069797711055).

Almost surely, 2^{72155620605221} is an apocalyptic number.

It is an amenable number.

72155620605221 is a deficient number, since it is larger than the sum of its proper divisors (402761083219).

72155620605221 is a wasteful number, since it uses less digits than its factorization.

72155620605221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511768183.

The product of its (nonzero) digits is 504000, while the sum is 44.

The spelling of 72155620605221 in words is "seventy-two trillion, one hundred fifty-five billion, six hundred twenty million, six hundred five thousand, two hundred twenty-one".