1378455917 has 2 divisors, whose sum is σ = 1378455918. Its totient is φ = 1378455916.

The previous prime is 1378455913. The next prime is 1378455919. The reversal of 1378455917 is 7195548731.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 910772041 + 467683876 = 30179^2 + 21626^2 .

It is a cyclic number.

It is not a de Polignac number, because 1378455917 - 2² = 1378455913 is a prime.

It is a super-2 number, since 2×1378455917² = 3800281430224621778, which contains 22 as substring.

Together with 1378455919, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1378455913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 689227958 + 689227959.

It is an arithmetic number, because the mean of its divisors is an integer number (689227959).

Almost surely, 2^1378455917 is an apocalyptic number.

It is an amenable number.

1378455917 is a deficient number, since it is larger than the sum of its proper divisors (1).

1378455917 is an equidigital number, since it uses as much as digits as its factorization.

1378455917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1058400, while the sum is 50.

The square root of 1378455917 is about 37127.5627667640. The cubic root of 1378455917 is about 1112.9208889640.

The spelling of 1378455917 in words is "one billion, three hundred seventy-eight million, four hundred fifty-five thousand, nine hundred seventeen".