138556751 has 4 divisors (see below), whose sum is σ = 143334600. Its totient is φ = 133778904.

The previous prime is 138556709. The next prime is 138556801. The reversal of 138556751 is 157655831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 157655831 = 881 ⋅178951.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138556751 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138556699 and 138556708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138556351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2388881 + ... + 2388938.

It is an arithmetic number, because the mean of its divisors is an integer number (35833650).

Almost surely, 2^138556751 is an apocalyptic number.

138556751 is a deficient number, since it is larger than the sum of its proper divisors (4777849).

138556751 is an equidigital number, since it uses as much as digits as its factorization.

138556751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4777848.

The product of its digits is 126000, while the sum is 41.

The square root of 138556751 is about 11771.0131679478. The cubic root of 138556751 is about 517.4589429647.

The spelling of 138556751 in words is "one hundred thirty-eight million, five hundred fifty-six thousand, seven hundred fifty-one".