25210021 has 2 divisors, whose sum is σ = 25210022. Its totient is φ = 25210020.

The previous prime is 25210007. The next prime is 25210027. The reversal of 25210021 is 12001252.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17313921 + 7896100 = 4161^2 + 2810^2 .

It is a cyclic number.

It is not a de Polignac number, because 25210021 - 2¹³ = 25201829 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 25209983 and 25210010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25210027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12605010 + 12605011.

It is an arithmetic number, because the mean of its divisors is an integer number (12605011).

Almost surely, 2^25210021 is an apocalyptic number.

It is an amenable number.

25210021 is a deficient number, since it is larger than the sum of its proper divisors (1).

25210021 is an equidigital number, since it uses as much as digits as its factorization.

25210021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 25210021 is about 5020.9581754880. The cubic root of 25210021 is about 293.2182984137.

Adding to 25210021 its reverse (12001252), we get a palindrome (37211273).

It can be divided in two parts, 25 and 210021, that multiplied together give a palindrome (5250525).

The spelling of 25210021 in words is "twenty-five million, two hundred ten thousand, twenty-one".