5138921 has 4 divisors (see below), whose sum is σ = 5144532. Its totient is φ = 5133312.

The previous prime is 5138891. The next prime is 5138923. The reversal of 5138921 is 1298315.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3841600 + 1297321 = 1960^2 + 1139^2 .

It is a cyclic number.

It is not a de Polignac number, because 5138921 - 2⁶ = 5138857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5138923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1076 + ... + 3381.

It is an arithmetic number, because the mean of its divisors is an integer number (1286133).

Almost surely, 2^5138921 is an apocalyptic number.

It is an amenable number.

5138921 is a deficient number, since it is larger than the sum of its proper divisors (5611).

5138921 is a wasteful number, since it uses less digits than its factorization.

5138921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5610.

The product of its digits is 2160, while the sum is 29.

The square root of 5138921 is about 2266.9188340124. The cubic root of 5138921 is about 172.5668270097.

Subtracting from 5138921 its reverse (1298315), we obtain a triangular number (3840606 = T₂₇₇₁).

The spelling of 5138921 in words is "five million, one hundred thirty-eight thousand, nine hundred twenty-one".