2139521 has 2 divisors, whose sum is σ = 2139522. Its totient is φ = 2139520.

The previous prime is 2139499. The next prime is 2139539. The reversal of 2139521 is 1259312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2131600 + 7921 = 1460^2 + 89^2 .

It is a cyclic number.

It is not a de Polignac number, because 2139521 - 2¹⁴ = 2123137 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2139541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1069760 + 1069761.

It is an arithmetic number, because the mean of its divisors is an integer number (1069761).

2^2139521 is an apocalyptic number.

It is an amenable number.

2139521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2139521 is an equidigital number, since it uses as much as digits as its factorization.

2139521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540, while the sum is 23.

The square root of 2139521 is about 1462.7101558409. The cubic root of 2139521 is about 128.8562587776.

The spelling of 2139521 in words is "two million, one hundred thirty-nine thousand, five hundred twenty-one".