1721040823 has 2 divisors, whose sum is σ = 1721040824. Its totient is φ = 1721040822.

The previous prime is 1721040809. The next prime is 1721040851. The reversal of 1721040823 is 3280401271.

It is an a-pointer prime, because the next prime (1721040851) can be obtained adding 1721040823 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1721040823 - 2⁵ = 1721040791 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1721040791 and 1721040800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721040863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860520411 + 860520412.

It is an arithmetic number, because the mean of its divisors is an integer number (860520412).

Almost surely, 2^1721040823 is an apocalyptic number.

1721040823 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721040823 is an equidigital number, since it uses as much as digits as its factorization.

1721040823 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 1721040823 is about 41485.4290444247. The cubic root of 1721040823 is about 1198.3869119923.

The spelling of 1721040823 in words is "one billion, seven hundred twenty-one million, forty thousand, eight hundred twenty-three".