221653581601 has 27 divisors (see below), whose sum is σ = 237956622003. Its totient is φ = 206436822480.

The previous prime is 221653581599. The next prime is 221653581613. The reversal of 221653581601 is 106185356122.

The square root of 221653581601 is 470801.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 162692029201 + 58961552400 = 403351^2 + 242820^2 .

It is not a de Polignac number, because 221653581601 - 2¹ = 221653581599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221653581641) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 635110375 + ... + 635110723.

Almost surely, 2^221653581601 is an apocalyptic number.

221653581601 is the 470801-st square number.

221653581601 is the 235401-st centered octagonal number.

It is an amenable number.

221653581601 is a deficient number, since it is larger than the sum of its proper divisors (16303040402).

221653581601 is an frugal number, since it uses more digits than its factorization.

221653581601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878 (or 439 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 40.

The spelling of 221653581601 in words is "two hundred twenty-one billion, six hundred fifty-three million, five hundred eighty-one thousand, six hundred one".