61138997138 has 4 divisors (see below), whose sum is σ = 91708495710. Its totient is φ = 30569498568.

The previous prime is 61138997119. The next prime is 61138997147. The reversal of 61138997138 is 83179983116.

61138997138 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.

It can be written as a sum of positive squares in only one way, i.e., 57606240169 + 3532756969 = 240013^2 + 59437^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15284749283 + ... + 15284749286.

Almost surely, 2^61138997138 is an apocalyptic number.

61138997138 is a deficient number, since it is larger than the sum of its proper divisors (30569498572).

61138997138 is a wasteful number, since it uses less digits than its factorization.

61138997138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30569498571.

The product of its digits is 1959552, while the sum is 56.

The spelling of 61138997138 in words is "sixty-one billion, one hundred thirty-eight million, nine hundred ninety-seven thousand, one hundred thirty-eight".