21641153514561 has 16 divisors (see below), whose sum is σ = 36641106480000. Its totient is φ = 12366373436784.

The previous prime is 21641153514553. The next prime is 21641153514611. The reversal of 21641153514561 is 16541535114612.

21641153514561 is a `hidden beast` number, since 2 + 1 + 6 + 4 + 11 + 535 + 1 + 45 + 61 = 666.

It is not a de Polignac number, because 21641153514561 - 2³ = 21641153514553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21641153513561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57251728686 + ... + 57251729063.

It is an arithmetic number, because the mean of its divisors is an integer number (2290069155000).

Almost surely, 2^{21641153514561} is an apocalyptic number.

21641153514561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21641153514561 is a deficient number, since it is larger than the sum of its proper divisors (14999952965439).

21641153514561 is a wasteful number, since it uses less digits than its factorization.

21641153514561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114503457765 (or 114503457759 counting only the distinct ones).

The product of its digits is 432000, while the sum is 45.

The spelling of 21641153514561 in words is "twenty-one trillion, six hundred forty-one billion, one hundred fifty-three million, five hundred fourteen thousand, five hundred sixty-one".