7138391121 has 9 divisors (see below), whose sum is σ = 10311375529. Its totient is φ = 4758758436.

The previous prime is 7138391101. The next prime is 7138391123. The reversal of 7138391121 is 1211938317.

The square root of 7138391121 is 84489.

It is a perfect power (a square), and thus also a powerful number.

7138391121 is a `hidden beast` number, since 71 + 383 + 91 + 121 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 7138391121 - 2¹¹ = 7138389073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7138391123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 239386 + ... + 267548.

Almost surely, 2^7138391121 is an apocalyptic number.

7138391121 is the 84489-th square number.

7138391121 is the 42245-th centered octagonal number.

It is an amenable number.

7138391121 is a deficient number, since it is larger than the sum of its proper divisors (3172984408).

7138391121 is an frugal number, since it uses more digits than its factorization.

7138391121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56332 (or 28166 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The cubic root of 7138391121 is about 1925.4553256760.

Multiplying 7138391121 by its sum of digits (36), we get a square (256982080356 = 506934²).

The spelling of 7138391121 in words is "seven billion, one hundred thirty-eight million, three hundred ninety-one thousand, one hundred twenty-one".