1645378349 has 2 divisors, whose sum is σ = 1645378350. Its totient is φ = 1645378348.

The previous prime is 1645378297. The next prime is 1645378363. The reversal of 1645378349 is 9438735461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1345569124 + 299809225 = 36682^2 + 17315^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645378349 is a prime.

It is a super-2 number, since 2×1645378349² = 5414539822715931602, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1645378297 and 1645378306.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1645368349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822689174 + 822689175.

It is an arithmetic number, because the mean of its divisors is an integer number (822689175).

Almost surely, 2^1645378349 is an apocalyptic number.

It is an amenable number.

1645378349 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645378349 is an equidigital number, since it uses as much as digits as its factorization.

1645378349 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2177280, while the sum is 50.

The square root of 1645378349 is about 40563.2635398090. The cubic root of 1645378349 is about 1180.5614366025.

The spelling of 1645378349 in words is "one billion, six hundred forty-five million, three hundred seventy-eight thousand, three hundred forty-nine".