1388813891 has 2 divisors, whose sum is σ = 1388813892. Its totient is φ = 1388813890.

The previous prime is 1388813887. The next prime is 1388813941. The reversal of 1388813891 is 1983188831.

It is an a-pointer prime, because the next prime (1388813941) can be obtained adding 1388813891 to its sum of digits (50).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1388813891 - 2² = 1388813887 is a prime.

It is not a weakly prime, because it can be changed into another prime (1388813821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 694406945 + 694406946.

It is an arithmetic number, because the mean of its divisors is an integer number (694406946).

Almost surely, 2^1388813891 is an apocalyptic number.

1388813891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1388813891 is an equidigital number, since it uses as much as digits as its factorization.

1388813891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 50.

The square root of 1388813891 is about 37266.7934091464. The cubic root of 1388813891 is about 1115.7015006856.

The spelling of 1388813891 in words is "one billion, three hundred eighty-eight million, eight hundred thirteen thousand, eight hundred ninety-one".