20591746221 has 4 divisors (see below), whose sum is σ = 27455661632. Its totient is φ = 13727830812.

The previous prime is 20591746207. The next prime is 20591746237. The reversal of 20591746221 is 12264719502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20591746221 - 2³⁴ = 3411877037 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20591746221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20591746921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3431957701 + ... + 3431957706.

It is an arithmetic number, because the mean of its divisors is an integer number (6863915408).

Almost surely, 2^20591746221 is an apocalyptic number.

It is an amenable number.

20591746221 is a deficient number, since it is larger than the sum of its proper divisors (6863915411).

20591746221 is an equidigital number, since it uses as much as digits as its factorization.

20591746221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6863915410.

The product of its (nonzero) digits is 60480, while the sum is 39.

The spelling of 20591746221 in words is "twenty billion, five hundred ninety-one million, seven hundred forty-six thousand, two hundred twenty-one".