1387979581 has 2 divisors, whose sum is σ = 1387979582. Its totient is φ = 1387979580.

The previous prime is 1387979539. The next prime is 1387979591. The reversal of 1387979581 is 1859797831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1291252356 + 96727225 = 35934^2 + 9835^2 .

It is an emirp because it is prime and its reverse (1859797831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1387979581 - 2¹⁷ = 1387848509 is a prime.

It is a super-2 number, since 2×1387979581² = 3852974634545871122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1387979521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693989790 + 693989791.

It is an arithmetic number, because the mean of its divisors is an integer number (693989791).

Almost surely, 2^1387979581 is an apocalyptic number.

It is an amenable number.

1387979581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1387979581 is an equidigital number, since it uses as much as digits as its factorization.

1387979581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3810240, while the sum is 58.

The square root of 1387979581 is about 37255.5979820483. The cubic root of 1387979581 is about 1115.4780420485.

The spelling of 1387979581 in words is "one billion, three hundred eighty-seven million, nine hundred seventy-nine thousand, five hundred eighty-one".