9138978961 has 8 divisors (see below), whose sum is σ = 10445662400. Its totient is φ = 7832574288.

The previous prime is 9138978943. The next prime is 9138978977. The reversal of 9138978961 is 1698798319.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9138978961 - 2¹³ = 9138970769 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 9138978961.

It is not an unprimeable number, because it can be changed into a prime (9138978931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6055 + ... + 135331.

It is an arithmetic number, because the mean of its divisors is an integer number (1305707800).

Almost surely, 2^9138978961 is an apocalyptic number.

It is an amenable number.

9138978961 is a deficient number, since it is larger than the sum of its proper divisors (1306683439).

9138978961 is a wasteful number, since it uses less digits than its factorization.

9138978961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139383.

The product of its digits is 5878656, while the sum is 61.

The square root of 9138978961 is about 95598.0070974286. The cubic root of 9138978961 is about 2090.7361372146.

The spelling of 9138978961 in words is "nine billion, one hundred thirty-eight million, nine hundred seventy-eight thousand, nine hundred sixty-one".