221405204255481 has 45 divisors (see below), whose sum is σ = 332976363182463. Its totient is φ = 146612571361200.

The previous prime is 221405204255471. The next prime is 221405204255513. The reversal of 221405204255481 is 184552402504122.

The square root of 221405204255481 is 14879691.

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

221405204255481 is a `hidden beast` number, since 2 + 2 + 1 + 4 + 0 + 52 + 0 + 42 + 554 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11533773691881 + 209871430563600 = 3396141^2 + 14486940^2 .

It is not a de Polignac number, because 221405204255481 - 2¹¹ = 221405204253433 is a prime.

It is a super-3 number, since 3×221405204255481³ (a number of 44 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (221405204255471) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 20221494595 + ... + 20221505543.

Almost surely, 2^{221405204255481} is an apocalyptic number.

221405204255481 is the 14879691-st square number.

221405204255481 is the 7439846-th centered octagonal number.

It is an amenable number.

221405204255481 is a deficient number, since it is larger than the sum of its proper divisors (111571158926982).

221405204255481 is an frugal number, since it uses more digits than its factorization.

221405204255481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22212 (or 11103 counting only the distinct ones).

The product of its (nonzero) digits is 1024000, while the sum is 45.

The spelling of 221405204255481 in words is "two hundred twenty-one trillion, four hundred five billion, two hundred four million, two hundred fifty-five thousand, four hundred eighty-one".