20120120001721 has 2 divisors, whose sum is σ = 20120120001722. Its totient is φ = 20120120001720.

The previous prime is 20120120001659. The next prime is 20120120001739. The reversal of 20120120001721 is 12710002102102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15012610401321 + 5107509600400 = 3874611^2 + 2259980^2 .

It is a cyclic number.

It is not a de Polignac number, because 20120120001721 - 2¹³ = 20120119993529 is a prime.

It is not a weakly prime, because it can be changed into another prime (20120120002721) 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 as a sum of consecutive naturals, namely, 10060060000860 + 10060060000861.

It is an arithmetic number, because the mean of its divisors is an integer number (10060060000861).

Almost surely, 2^{20120120001721} is an apocalyptic number.

It is an amenable number.

20120120001721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20120120001721 is an equidigital number, since it uses as much as digits as its factorization.

20120120001721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 19.

Adding to 20120120001721 its reverse (12710002102102), we get a palindrome (32830122103823).

The spelling of 20120120001721 in words is "twenty trillion, one hundred twenty billion, one hundred twenty million, one thousand, seven hundred twenty-one".