20551433505221 has 2 divisors, whose sum is σ = 20551433505222. Its totient is φ = 20551433505220.

The previous prime is 20551433505203. The next prime is 20551433505277. The reversal of 20551433505221 is 12250533415502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20464856916100 + 86576589121 = 4523810^2 + 294239^2 .

It is a cyclic number.

It is not a de Polignac number, because 20551433505221 - 2²⁶ = 20551366396357 is a prime.

It is a super-2 number, since 2×20551433505221² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20551433505721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10275716752610 + 10275716752611.

It is an arithmetic number, because the mean of its divisors is an integer number (10275716752611).

Almost surely, 2^{20551433505221} is an apocalyptic number.

It is an amenable number.

20551433505221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20551433505221 is an equidigital number, since it uses as much as digits as its factorization.

20551433505221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180000, while the sum is 38.

The spelling of 20551433505221 in words is "twenty trillion, five hundred fifty-one billion, four hundred thirty-three million, five hundred five thousand, two hundred twenty-one".