663025021 has 2 divisors, whose sum is σ = 663025022. Its totient is φ = 663025020.

The previous prime is 663024997. The next prime is 663025037. The reversal of 663025021 is 120520366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 467164996 + 195860025 = 21614^2 + 13995^2 .

It is a cyclic number.

It is not a de Polignac number, because 663025021 - 2¹¹ = 663022973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (663025061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331512510 + 331512511.

It is an arithmetic number, because the mean of its divisors is an integer number (331512511).

Almost surely, 2^663025021 is an apocalyptic number.

It is an amenable number.

663025021 is a deficient number, since it is larger than the sum of its proper divisors (1).

663025021 is an equidigital number, since it uses as much as digits as its factorization.

663025021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 663025021 is about 25749.2722421431. The cubic root of 663025021 is about 871.9869243929.

Adding to 663025021 its reverse (120520366), we get a palindrome (783545387).

The spelling of 663025021 in words is "six hundred sixty-three million, twenty-five thousand, twenty-one".