21660727222251 has 24 divisors (see below), whose sum is σ = 34197367036560. Its totient is φ = 13130727863616.

The previous prime is 21660727222241. The next prime is 21660727222289. The reversal of 21660727222251 is 15222272706612.

21660727222251 is a `hidden beast` number, since 2 + 16 + 607 + 2 + 7 + 2 + 2 + 2 + 25 + 1 = 666.

It is not a de Polignac number, because 21660727222251 - 2¹¹ = 21660727220203 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21660727222197 and 21660727222206.

It is not an unprimeable number, because it can be changed into a prime (21660727222241) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1381592316 + ... + 1381607993.

It is an arithmetic number, because the mean of its divisors is an integer number (1424890293190).

Almost surely, 2^{21660727222251} is an apocalyptic number.

21660727222251 is a deficient number, since it is larger than the sum of its proper divisors (12536639814309).

21660727222251 is a wasteful number, since it uses less digits than its factorization.

21660727222251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2763200395 (or 2763200392 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

Adding to 21660727222251 its reverse (15222272706612), we get a palindrome (36882999928863).

The spelling of 21660727222251 in words is "twenty-one trillion, six hundred sixty billion, seven hundred twenty-seven million, two hundred twenty-two thousand, two hundred fifty-one".