1387555649 has 2 divisors, whose sum is σ = 1387555650. Its totient is φ = 1387555648.

The previous prime is 1387555621. The next prime is 1387555709. The reversal of 1387555649 is 9465557831.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 957283600 + 430272049 = 30940^2 + 20743^2 .

It is a cyclic number.

It is not a de Polignac number, because 1387555649 - 2¹² = 1387551553 is a prime.

It is a super-2 number, since 2×1387555649² = 3850621358143622402, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1387555649.

It is not a weakly prime, because it can be changed into another prime (1387555049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 693777824 + 693777825.

It is an arithmetic number, because the mean of its divisors is an integer number (693777825).

Almost surely, 2^1387555649 is an apocalyptic number.

It is an amenable number.

1387555649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1387555649 is an equidigital number, since it uses as much as digits as its factorization.

1387555649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536000, while the sum is 53.

The square root of 1387555649 is about 37249.9080401549. The cubic root of 1387555649 is about 1115.3644632907.

The spelling of 1387555649 in words is "one billion, three hundred eighty-seven million, five hundred fifty-five thousand, six hundred forty-nine".