4128521 has 2 divisors, whose sum is σ = 4128522. Its totient is φ = 4128520.

The previous prime is 4128517. The next prime is 4128533. The reversal of 4128521 is 1258214.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2676496 + 1452025 = 1636^2 + 1205^2 .

It is a cyclic number.

It is not a de Polignac number, because 4128521 - 2² = 4128517 is a prime.

It is a Sophie Germain prime.

It is an Ulam number.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (4128511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2064260 + 2064261.

It is an arithmetic number, because the mean of its divisors is an integer number (2064261).

Almost surely, 2^4128521 is an apocalyptic number.

It is an amenable number.

4128521 is a deficient number, since it is larger than the sum of its proper divisors (1).

4128521 is an equidigital number, since it uses as much as digits as its factorization.

4128521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 640, while the sum is 23.

The square root of 4128521 is about 2031.8762265453. The cubic root of 4128521 is about 160.4223347485.

The spelling of 4128521 in words is "four million, one hundred twenty-eight thousand, five hundred twenty-one".