253028021 has 2 divisors, whose sum is σ = 253028022. Its totient is φ = 253028020.

The previous prime is 253028003. The next prime is 253028023. The reversal of 253028021 is 120820352.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 252651025 + 376996 = 15895^2 + 614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-253028021 is a prime.

It is a super-2 number, since 2×253028021² = 128046358822352882, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 253028023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (253028023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 126514010 + 126514011.

It is an arithmetic number, because the mean of its divisors is an integer number (126514011).

Almost surely, 2^253028021 is an apocalyptic number.

It is an amenable number.

253028021 is a deficient number, since it is larger than the sum of its proper divisors (1).

253028021 is an equidigital number, since it uses as much as digits as its factorization.

253028021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 253028021 is about 15906.8545287873. The cubic root of 253028021 is about 632.4937032186.

Adding to 253028021 its reverse (120820352), we get a palindrome (373848373).

The spelling of 253028021 in words is "two hundred fifty-three million, twenty-eight thousand, twenty-one".