1388911409 has 4 divisors (see below), whose sum is σ = 1389154404. Its totient is φ = 1388668416.

The previous prime is 1388911393. The next prime is 1388911453. The reversal of 1388911409 is 9041198831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9041198831 = 7 ⋅1291599833.

It can be written as a sum of positive squares in 2 ways, for example, as 1286800384 + 102111025 = 35872^2 + 10105^2 .

It is a cyclic number.

It is not a de Polignac number, because 1388911409 - 2⁴ = 1388911393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1388911409.

It is not an unprimeable number, because it can be changed into a prime (1388911009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112712 + ... + 124425.

It is an arithmetic number, because the mean of its divisors is an integer number (347288601).

Almost surely, 2^1388911409 is an apocalyptic number.

It is an amenable number.

1388911409 is a deficient number, since it is larger than the sum of its proper divisors (242995).

1388911409 is an equidigital number, since it uses as much as digits as its factorization.

1388911409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242994.

The product of its (nonzero) digits is 62208, while the sum is 44.

The square root of 1388911409 is about 37268.1017627676. The cubic root of 1388911409 is about 1115.7276137195.

The spelling of 1388911409 in words is "one billion, three hundred eighty-eight million, nine hundred eleven thousand, four hundred nine".