21530322157 has 2 divisors, whose sum is σ = 21530322158. Its totient is φ = 21530322156.

The previous prime is 21530322133. The next prime is 21530322173. The reversal of 21530322157 is 75122303512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21391695081 + 138627076 = 146259^2 + 11774^2 .

It is a cyclic number.

It is not a de Polignac number, because 21530322157 - 2⁷ = 21530322029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21530322257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765161078 + 10765161079.

It is an arithmetic number, because the mean of its divisors is an integer number (10765161079).

Almost surely, 2^21530322157 is an apocalyptic number.

It is an amenable number.

21530322157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530322157 is an equidigital number, since it uses as much as digits as its factorization.

21530322157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 31.

Adding to 21530322157 its reverse (75122303512), we get a palindrome (96652625669).

The spelling of 21530322157 in words is "twenty-one billion, five hundred thirty million, three hundred twenty-two thousand, one hundred fifty-seven".