20516535454221 has 12 divisors (see below), whose sum is σ = 29636273493372. Its totient is φ = 13677100531776.

The previous prime is 20516535454141. The next prime is 20516535454231. The reversal of 20516535454221 is 12245453561502.

20516535454221 is a `hidden beast` number, since 2 + 0 + 5 + 1 + 6 + 53 + 54 + 542 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 291178952100 + 20225356502121 = 539610^2 + 4497261^2 .

It is not a de Polignac number, because 20516535454221 - 2²⁶ = 20516468345357 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20516535454231) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 48927216 + ... + 49344761.

It is an arithmetic number, because the mean of its divisors is an integer number (2469689457781).

Almost surely, 2^{20516535454221} is an apocalyptic number.

It is an amenable number.

20516535454221 is a deficient number, since it is larger than the sum of its proper divisors (9119738039151).

20516535454221 is a wasteful number, since it uses less digits than its factorization.

20516535454221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98295180 (or 98295177 counting only the distinct ones).

The product of its (nonzero) digits is 1440000, while the sum is 45.

The spelling of 20516535454221 in words is "twenty trillion, five hundred sixteen billion, five hundred thirty-five million, four hundred fifty-four thousand, two hundred twenty-one".