7138123775021 has 4 divisors (see below), whose sum is σ = 7138287758844. Its totient is φ = 7137959791200.

The previous prime is 7138123774987. The next prime is 7138123775051. The reversal of 7138123775021 is 1205773218317.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2128199557225 + 5009924217796 = 1458835^2 + 2238286^2 .

It is a cyclic number.

It is not a de Polignac number, because 7138123775021 - 2¹⁰ = 7138123773997 is a prime.

It is a super-2 number, since 2×7138123775021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7138123775051) 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, 81926600 + ... + 82013681.

It is an arithmetic number, because the mean of its divisors is an integer number (1784571939711).

Almost surely, 2^{7138123775021} is an apocalyptic number.

It is an amenable number.

7138123775021 is a deficient number, since it is larger than the sum of its proper divisors (163983823).

7138123775021 is a wasteful number, since it uses less digits than its factorization.

7138123775021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163983822.

The product of its (nonzero) digits is 493920, while the sum is 47.

The spelling of 7138123775021 in words is "seven trillion, one hundred thirty-eight billion, one hundred twenty-three million, seven hundred seventy-five thousand, twenty-one".