245244520021 has 2 divisors, whose sum is σ = 245244520022. Its totient is φ = 245244520020.

The previous prime is 245244520013. The next prime is 245244520049. The reversal of 245244520021 is 120025442542.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216075295921 + 29169224100 = 464839^2 + 170790^2 .

It is a cyclic number.

It is not a de Polignac number, because 245244520021 - 2³ = 245244520013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (245244529021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 122622260010 + 122622260011.

It is an arithmetic number, because the mean of its divisors is an integer number (122622260011).

Almost surely, 2^245244520021 is an apocalyptic number.

It is an amenable number.

245244520021 is a deficient number, since it is larger than the sum of its proper divisors (1).

245244520021 is an equidigital number, since it uses as much as digits as its factorization.

245244520021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25600, while the sum is 31.

Adding to 245244520021 its reverse (120025442542), we get a palindrome (365269962563).

The spelling of 245244520021 in words is "two hundred forty-five billion, two hundred forty-four million, five hundred twenty thousand, twenty-one".