1721115397 has 2 divisors, whose sum is σ = 1721115398. Its totient is φ = 1721115396.

The previous prime is 1721115367. The next prime is 1721115439. The reversal of 1721115397 is 7935111271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1197575236 + 523540161 = 34606^2 + 22881^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721115397 - 2²³ = 1712726789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721115367) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860557698 + 860557699.

It is an arithmetic number, because the mean of its divisors is an integer number (860557699).

Almost surely, 2^1721115397 is an apocalyptic number.

It is an amenable number.

1721115397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721115397 is an equidigital number, since it uses as much as digits as its factorization.

1721115397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13230, while the sum is 37.

The square root of 1721115397 is about 41486.3278321907. The cubic root of 1721115397 is about 1198.4042207460.

The spelling of 1721115397 in words is "one billion, seven hundred twenty-one million, one hundred fifteen thousand, three hundred ninety-seven".