1618720393 has 2 divisors, whose sum is σ = 1618720394. Its totient is φ = 1618720392.

The previous prime is 1618720379. The next prime is 1618720421. The reversal of 1618720393 is 3930278161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1479787024 + 138933369 = 38468^2 + 11787^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1618720393 is a prime.

It is not a weakly prime, because it can be changed into another prime (1618720343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 809360196 + 809360197.

It is an arithmetic number, because the mean of its divisors is an integer number (809360197).

Almost surely, 2^1618720393 is an apocalyptic number.

It is an amenable number.

1618720393 is a deficient number, since it is larger than the sum of its proper divisors (1).

1618720393 is an equidigital number, since it uses as much as digits as its factorization.

1618720393 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 1618720393 is about 40233.3244090020. The cubic root of 1618720393 is about 1174.1509829936.

The spelling of 1618720393 in words is "one billion, six hundred eighteen million, seven hundred twenty thousand, three hundred ninety-three".