245021521 has 2 divisors, whose sum is σ = 245021522. Its totient is φ = 245021520.

The previous prime is 245021519. The next prime is 245021591. The reversal of 245021521 is 125120542.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 243360000 + 1661521 = 15600^2 + 1289^2 .

It is a cyclic number.

It is not a de Polignac number, because 245021521 - 2¹ = 245021519 is a prime.

Together with 245021519, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 245021492 and 245021501.

It is not a weakly prime, because it can be changed into another prime (245021501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 122510760 + 122510761.

It is an arithmetic number, because the mean of its divisors is an integer number (122510761).

Almost surely, 2^245021521 is an apocalyptic number.

It is an amenable number.

245021521 is a deficient number, since it is larger than the sum of its proper divisors (1).

245021521 is an equidigital number, since it uses as much as digits as its factorization.

245021521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 245021521 is about 15653.1632905301. The cubic root of 245021521 is about 625.7507956483.

It can be divided in two parts, 245021 and 521, that added together give a palindrome (245542).

The spelling of 245021521 in words is "two hundred forty-five million, twenty-one thousand, five hundred twenty-one".