53231621 has 2 divisors, whose sum is σ = 53231622. Its totient is φ = 53231620.

The previous prime is 53231609. The next prime is 53231623. The reversal of 53231621 is 12613235.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38130625 + 15100996 = 6175^2 + 3886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-53231621 is a prime.

Together with 53231623, 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 (53231623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26615810 + 26615811.

It is an arithmetic number, because the mean of its divisors is an integer number (26615811).

Almost surely, 2^53231621 is an apocalyptic number.

It is an amenable number.

53231621 is a deficient number, since it is larger than the sum of its proper divisors (1).

53231621 is an equidigital number, since it uses as much as digits as its factorization.

53231621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 23.

The square root of 53231621 is about 7296.0003426535. Note that the first 3 decimals coincide. The cubic root of 53231621 is about 376.1749718499.

Adding to 53231621 its reverse (12613235), we get a palindrome (65844856).

The spelling of 53231621 in words is "fifty-three million, two hundred thirty-one thousand, six hundred twenty-one".