1387787585981 has 2 divisors, whose sum is σ = 1387787585982. Its totient is φ = 1387787585980.

The previous prime is 1387787585953. The next prime is 1387787585983. The reversal of 1387787585981 is 1895857877831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 702857549956 + 684930036025 = 838366^2 + 827605^2 .

It is a cyclic number.

It is not a de Polignac number, because 1387787585981 - 2³⁰ = 1386713844157 is a prime.

It is a super-2 number, since 2×1387787585981² (a number of 25 digits) contains 22 as substring.

Together with 1387787585983, 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 (1387787585983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693893792990 + 693893792991.

It is an arithmetic number, because the mean of its divisors is an integer number (693893792991).

Almost surely, 2^{1387787585981} is an apocalyptic number.

It is an amenable number.

1387787585981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1387787585981 is an equidigital number, since it uses as much as digits as its factorization.

1387787585981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 948326400, while the sum is 77.

The spelling of 1387787585981 in words is "one trillion, three hundred eighty-seven billion, seven hundred eighty-seven million, five hundred eighty-five thousand, nine hundred eighty-one".