6440155387 has 2 divisors, whose sum is σ = 6440155388. Its totient is φ = 6440155386.

The previous prime is 6440155363. The next prime is 6440155409. The reversal of 6440155387 is 7835510446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6440155387 - 2³¹ = 4292671739 is a prime.

It is not a weakly prime, because it can be changed into another prime (6440155327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3220077693 + 3220077694.

It is an arithmetic number, because the mean of its divisors is an integer number (3220077694).

Almost surely, 2^6440155387 is an apocalyptic number.

6440155387 is a deficient number, since it is larger than the sum of its proper divisors (1).

6440155387 is an equidigital number, since it uses as much as digits as its factorization.

6440155387 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 403200, while the sum is 43.

The square root of 6440155387 is about 80250.5787331157. The cubic root of 6440155387 is about 1860.5104571729.

The spelling of 6440155387 in words is "six billion, four hundred forty million, one hundred fifty-five thousand, three hundred eighty-seven".