53309021 has 2 divisors, whose sum is σ = 53309022. Its totient is φ = 53309020.

The previous prime is 53308973. The next prime is 53309023. The reversal of 53309021 is 12090335.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44368921 + 8940100 = 6661^2 + 2990^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-53309021 is a prime.

Together with 53309023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (53309023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26654510 + 26654511.

It is an arithmetic number, because the mean of its divisors is an integer number (26654511).

Almost surely, 2^53309021 is an apocalyptic number.

It is an amenable number.

53309021 is a deficient number, since it is larger than the sum of its proper divisors (1).

53309021 is an equidigital number, since it uses as much as digits as its factorization.

53309021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 810, while the sum is 23.

The square root of 53309021 is about 7301.3026919859. The cubic root of 53309021 is about 376.3572059050.

Adding to 53309021 its reverse (12090335), we get a palindrome (65399356).

The spelling of 53309021 in words is "fifty-three million, three hundred nine thousand, twenty-one".