21721722223051 has 2 divisors, whose sum is σ = 21721722223052. Its totient is φ = 21721722223050.

The previous prime is 21721722222973. The next prime is 21721722223081. The reversal of 21721722223051 is 15032222712712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21721722223051 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21721722223051.

It is not a weakly prime, because it can be changed into another prime (21721722223081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10860861111525 + 10860861111526.

It is an arithmetic number, because the mean of its divisors is an integer number (10860861111526).

Almost surely, 2^{21721722223051} is an apocalyptic number.

21721722223051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21721722223051 is an equidigital number, since it uses as much as digits as its factorization.

21721722223051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 47040, while the sum is 37.

Adding to 21721722223051 its reverse (15032222712712), we get a palindrome (36753944935763).

The spelling of 21721722223051 in words is "twenty-one trillion, seven hundred twenty-one billion, seven hundred twenty-two million, two hundred twenty-three thousand, fifty-one".