1945903681 has 2 divisors, whose sum is σ = 1945903682. Its totient is φ = 1945903680.

The previous prime is 1945903651. The next prime is 1945903703. The reversal of 1945903681 is 1863095491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1799880625 + 146023056 = 42425^2 + 12084^2 .

It is an emirp because it is prime and its reverse (1863095491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1945903681 - 2¹⁹ = 1945379393 is a prime.

It is a super-2 number, since 2×1945903681² = 7573082271458699522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1945903651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 972951840 + 972951841.

It is an arithmetic number, because the mean of its divisors is an integer number (972951841).

Almost surely, 2^1945903681 is an apocalyptic number.

It is an amenable number.

1945903681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1945903681 is an equidigital number, since it uses as much as digits as its factorization.

1945903681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 233280, while the sum is 46.

The square root of 1945903681 is about 44112.3982685140. The cubic root of 1945903681 is about 1248.4575494065.

The spelling of 1945903681 in words is "one billion, nine hundred forty-five million, nine hundred three thousand, six hundred eighty-one".