1721723651 has 2 divisors, whose sum is σ = 1721723652. Its totient is φ = 1721723650.

The previous prime is 1721723623. The next prime is 1721723681. The reversal of 1721723651 is 1563271271.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1721723651 - 2¹⁰ = 1721722627 is a prime.

It is not a weakly prime, because it can be changed into another prime (1721723621) 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 as a sum of consecutive naturals, namely, 860861825 + 860861826.

It is an arithmetic number, because the mean of its divisors is an integer number (860861826).

Almost surely, 2^1721723651 is an apocalyptic number.

1721723651 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721723651 is an equidigital number, since it uses as much as digits as its factorization.

1721723651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17640, while the sum is 35.

The square root of 1721723651 is about 41493.6579611873. The cubic root of 1721723651 is about 1198.5453788788.

The spelling of 1721723651 in words is "one billion, seven hundred twenty-one million, seven hundred twenty-three thousand, six hundred fifty-one".