21261162130157 has 2 divisors, whose sum is σ = 21261162130158. Its totient is φ = 21261162130156.

The previous prime is 21261162130099. The next prime is 21261162130177. The reversal of 21261162130157 is 75103126116212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21218865683236 + 42296446921 = 4606394^2 + 205661^2 .

It is a cyclic number.

It is not a de Polignac number, because 21261162130157 - 2⁴⁴ = 3668976085741 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21261162130157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21261162130177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630581065078 + 10630581065079.

It is an arithmetic number, because the mean of its divisors is an integer number (10630581065079).

Almost surely, 2^{21261162130157} is an apocalyptic number.

It is an amenable number.

21261162130157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21261162130157 is an equidigital number, since it uses as much as digits as its factorization.

21261162130157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 38.

Adding to 21261162130157 its reverse (75103126116212), we get a palindrome (96364288246369).

The spelling of 21261162130157 in words is "twenty-one trillion, two hundred sixty-one billion, one hundred sixty-two million, one hundred thirty thousand, one hundred fifty-seven".