1720622371421 has 2 divisors, whose sum is σ = 1720622371422. Its totient is φ = 1720622371420.

The previous prime is 1720622371409. The next prime is 1720622371483. The reversal of 1720622371421 is 1241732260271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1036008444025 + 684613927396 = 1017845^2 + 827414^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1720622371421 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1720622371921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860311185710 + 860311185711.

It is an arithmetic number, because the mean of its divisors is an integer number (860311185711).

Almost surely, 2^{1720622371421} is an apocalyptic number.

It is an amenable number.

1720622371421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720622371421 is an equidigital number, since it uses as much as digits as its factorization.

1720622371421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56448, while the sum is 38.

The spelling of 1720622371421 in words is "one trillion, seven hundred twenty billion, six hundred twenty-two million, three hundred seventy-one thousand, four hundred twenty-one".