20581221733 has 4 divisors (see below), whose sum is σ = 20582041120. Its totient is φ = 20580402348.

The previous prime is 20581221719. The next prime is 20581221737. The reversal of 20581221733 is 33712218502.

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 a cyclic number.

It is not a de Polignac number, because 20581221733 - 2⁵ = 20581221701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20581221737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 370785 + ... + 422662.

It is an arithmetic number, because the mean of its divisors is an integer number (5145510280).

Almost surely, 2^20581221733 is an apocalyptic number.

It is an amenable number.

20581221733 is a deficient number, since it is larger than the sum of its proper divisors (819387).

20581221733 is an equidigital number, since it uses as much as digits as its factorization.

20581221733 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819386.

The product of its (nonzero) digits is 20160, while the sum is 34.

The spelling of 20581221733 in words is "twenty billion, five hundred eighty-one million, two hundred twenty-one thousand, seven hundred thirty-three".