20643721214521 has 8 divisors (see below), whose sum is σ = 21311365376000. Its totient is φ = 19976184407520.

The previous prime is 20643721214497. The next prime is 20643721214563. The reversal of 20643721214521 is 12541212734602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20643721214521 - 2⁵ = 20643721214489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20643721614521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26447721 + ... + 27217078.

It is an arithmetic number, because the mean of its divisors is an integer number (2663920672000).

Almost surely, 2^{20643721214521} is an apocalyptic number.

It is an amenable number.

20643721214521 is a deficient number, since it is larger than the sum of its proper divisors (667644161479).

20643721214521 is a wasteful number, since it uses less digits than its factorization.

20643721214521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53677239.

The product of its (nonzero) digits is 161280, while the sum is 40.

The spelling of 20643721214521 in words is "twenty trillion, six hundred forty-three billion, seven hundred twenty-one million, two hundred fourteen thousand, five hundred twenty-one".