1721950817 has 2 divisors, whose sum is σ = 1721950818. Its totient is φ = 1721950816.

The previous prime is 1721950801. The next prime is 1721950819. The reversal of 1721950817 is 7180591271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 922701376 + 799249441 = 30376^2 + 28271^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721950817 - 2⁴ = 1721950801 is a prime.

It is a super-2 number, since 2×1721950817² = 5930229232333934978, which contains 22 as substring.

Together with 1721950819, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1721950819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860975408 + 860975409.

It is an arithmetic number, because the mean of its divisors is an integer number (860975409).

Almost surely, 2^1721950817 is an apocalyptic number.

It is an amenable number.

1721950817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721950817 is an equidigital number, since it uses as much as digits as its factorization.

1721950817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35280, while the sum is 41.

The square root of 1721950817 is about 41496.3952289834. The cubic root of 1721950817 is about 1198.5980889998.

The spelling of 1721950817 in words is "one billion, seven hundred twenty-one million, nine hundred fifty thousand, eight hundred seventeen".