9138491261 has 4 divisors (see below), whose sum is σ = 9535816992. Its totient is φ = 8741165532.

The previous prime is 9138491251. The next prime is 9138491267. The reversal of 9138491261 is 1621948319.

9138491261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1621948319 = 19 ⋅85365701.

It is a cyclic number.

It is not a de Polignac number, because 9138491261 - 2²² = 9134296957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9138491267) 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 3 ways as a sum of consecutive naturals, for example, 198662831 + ... + 198662876.

It is an arithmetic number, because the mean of its divisors is an integer number (2383954248).

Almost surely, 2^9138491261 is an apocalyptic number.

It is an amenable number.

9138491261 is a deficient number, since it is larger than the sum of its proper divisors (397325731).

9138491261 is a wasteful number, since it uses less digits than its factorization.

9138491261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397325730.

The product of its digits is 93312, while the sum is 44.

The square root of 9138491261 is about 95595.4562780052. The cubic root of 9138491261 is about 2090.6989459646.

The spelling of 9138491261 in words is "nine billion, one hundred thirty-eight million, four hundred ninety-one thousand, two hundred sixty-one".