1377457661 has 2 divisors, whose sum is σ = 1377457662. Its totient is φ = 1377457660.

The previous prime is 1377457643. The next prime is 1377457663. The reversal of 1377457661 is 1667547731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1309064761 + 68392900 = 36181^2 + 8270^2 .

It is a cyclic number.

It is not a de Polignac number, because 1377457661 - 2¹⁴ = 1377441277 is a prime.

Together with 1377457663, 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 (1377457663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 688728830 + 688728831.

It is an arithmetic number, because the mean of its divisors is an integer number (688728831).

Almost surely, 2^1377457661 is an apocalyptic number.

It is an amenable number.

1377457661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1377457661 is an equidigital number, since it uses as much as digits as its factorization.

1377457661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 740880, while the sum is 47.

The square root of 1377457661 is about 37114.1167347412. The cubic root of 1377457661 is about 1112.6521708440.

The spelling of 1377457661 in words is "one billion, three hundred seventy-seven million, four hundred fifty-seven thousand, six hundred sixty-one".