1388086721 has 16 divisors (see below), whose sum is σ = 1642288128. Its totient is φ = 1148083200.

The previous prime is 1388086699. The next prime is 1388086727. The reversal of 1388086721 is 1276808831.

It is a cyclic number.

It is not a de Polignac number, because 1388086721 - 2¹⁰ = 1388085697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1388086727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67541 + ... + 85661.

It is an arithmetic number, because the mean of its divisors is an integer number (102643008).

Almost surely, 2^1388086721 is an apocalyptic number.

It is an amenable number.

1388086721 is a deficient number, since it is larger than the sum of its proper divisors (254201407).

1388086721 is a wasteful number, since it uses less digits than its factorization.

1388086721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18512.

The product of its (nonzero) digits is 129024, while the sum is 44.

The square root of 1388086721 is about 37257.0358590159. The cubic root of 1388086721 is about 1115.5067430573.

The spelling of 1388086721 in words is "one billion, three hundred eighty-eight million, eighty-six thousand, seven hundred twenty-one".