21125334157 has 2 divisors, whose sum is σ = 21125334158. Its totient is φ = 21125334156.

The previous prime is 21125334127. The next prime is 21125334179. The reversal of 21125334157 is 75143352112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21096400516 + 28933641 = 145246^2 + 5379^2 .

It is a cyclic number.

It is not a de Polignac number, because 21125334157 - 2¹⁹ = 21124809869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21125334127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10562667078 + 10562667079.

It is an arithmetic number, because the mean of its divisors is an integer number (10562667079).

Almost surely, 2^21125334157 is an apocalyptic number.

It is an amenable number.

21125334157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21125334157 is an equidigital number, since it uses as much as digits as its factorization.

21125334157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 34.

Adding to 21125334157 its reverse (75143352112), we get a palindrome (96268686269).

The spelling of 21125334157 in words is "twenty-one billion, one hundred twenty-five million, three hundred thirty-four thousand, one hundred fifty-seven".