2521921 has 2 divisors, whose sum is σ = 2521922. Its totient is φ = 2521920.

The previous prime is 2521919. The next prime is 2521949. The reversal of 2521921 is 1291252.

2521921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2016400 + 505521 = 1420^2 + 711^2 .

It is a cyclic number.

It is not a de Polignac number, because 2521921 - 2¹ = 2521919 is a prime.

Together with 2521919, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 2521892 and 2521901.

It is not a weakly prime, because it can be changed into another prime (2521901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1260960 + 1260961.

It is an arithmetic number, because the mean of its divisors is an integer number (1260961).

2^2521921 is an apocalyptic number.

It is an amenable number.

2521921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2521921 is an equidigital number, since it uses as much as digits as its factorization.

2521921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 22.

The square root of 2521921 is about 1588.0557295007. The cubic root of 2521921 is about 136.1164120045.

The spelling of 2521921 in words is "two million, five hundred twenty-one thousand, nine hundred twenty-one".