1721740381 has 2 divisors, whose sum is σ = 1721740382. Its totient is φ = 1721740380.

The previous prime is 1721740367. The next prime is 1721740387. The reversal of 1721740381 is 1830471271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1194808356 + 526932025 = 34566^2 + 22955^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721740381 - 2⁹ = 1721739869 is a prime.

It is a super-2 number, since 2×1721740381² = 5928779879132050322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721740387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860870190 + 860870191.

It is an arithmetic number, because the mean of its divisors is an integer number (860870191).

Almost surely, 2^1721740381 is an apocalyptic number.

It is an amenable number.

1721740381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721740381 is an equidigital number, since it uses as much as digits as its factorization.

1721740381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 1721740381 is about 41493.8595577707. The cubic root of 1721740381 is about 1198.5492609573.

The spelling of 1721740381 in words is "one billion, seven hundred twenty-one million, seven hundred forty thousand, three hundred eighty-one".