21213211157 has 2 divisors, whose sum is σ = 21213211158. Its totient is φ = 21213211156.

The previous prime is 21213211141. The next prime is 21213211171. The reversal of 21213211157 is 75111231212.

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., 11081983441 + 10131227716 = 105271^2 + 100654^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213211157 - 2⁴ = 21213211141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213211127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606605578 + 10606605579.

It is an arithmetic number, because the mean of its divisors is an integer number (10606605579).

Almost surely, 2^21213211157 is an apocalyptic number.

It is an amenable number.

21213211157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213211157 is an equidigital number, since it uses as much as digits as its factorization.

21213211157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 26.

Adding to 21213211157 its reverse (75111231212), we get a palindrome (96324442369).

The spelling of 21213211157 in words is "twenty-one billion, two hundred thirteen million, two hundred eleven thousand, one hundred fifty-seven".