21020221012157 has 2 divisors, whose sum is σ = 21020221012158. Its totient is φ = 21020221012156.

The previous prime is 21020221012097. The next prime is 21020221012159. The reversal of 21020221012157 is 75121012202012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20824017195556 + 196203816601 = 4563334^2 + 442949^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020221012157 - 2¹⁰ = 21020221011133 is a prime.

It is a super-3 number, since 3×21020221012157³ (a number of 41 digits) contains 333 as substring.

Together with 21020221012159, 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 (21020221012159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510110506078 + 10510110506079.

It is an arithmetic number, because the mean of its divisors is an integer number (10510110506079).

Almost surely, 2^{21020221012157} is an apocalyptic number.

It is an amenable number.

21020221012157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020221012157 is an equidigital number, since it uses as much as digits as its factorization.

21020221012157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 26.

Adding to 21020221012157 its reverse (75121012202012), we get a palindrome (96141233214169).

The spelling of 21020221012157 in words is "twenty-one trillion, twenty billion, two hundred twenty-one million, twelve thousand, one hundred fifty-seven".