20456646521 has 8 divisors (see below), whose sum is σ = 20827458624. Its totient is φ = 20086978320.

The previous prime is 20456646493. The next prime is 20456646523. The reversal of 20456646521 is 12564665402.

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 20456646521 - 2³⁴ = 3276777337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20456646523) 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, 249845 + ... + 321458.

It is an arithmetic number, because the mean of its divisors is an integer number (2603432328).

Almost surely, 2^20456646521 is an apocalyptic number.

It is an amenable number.

20456646521 is a deficient number, since it is larger than the sum of its proper divisors (370812103).

20456646521 is an equidigital number, since it uses as much as digits as its factorization.

20456646521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 571951.

The product of its (nonzero) digits is 345600, while the sum is 41.

The spelling of 20456646521 in words is "twenty billion, four hundred fifty-six million, six hundred forty-six thousand, five hundred twenty-one".