21040320321157 has 2 divisors, whose sum is σ = 21040320321158. Its totient is φ = 21040320321156.

The previous prime is 21040320321143. The next prime is 21040320321247. The reversal of 21040320321157 is 75112302304012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18271444289121 + 2768876032036 = 4274511^2 + 1663994^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21040320321157 is a prime.

It is a super-3 number, since 3×21040320321157³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21040320321127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10520160160578 + 10520160160579.

It is an arithmetic number, because the mean of its divisors is an integer number (10520160160579).

Almost surely, 2^{21040320321157} is an apocalyptic number.

It is an amenable number.

21040320321157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21040320321157 is an equidigital number, since it uses as much as digits as its factorization.

21040320321157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 31.

Adding to 21040320321157 its reverse (75112302304012), we get a palindrome (96152622625169).

The spelling of 21040320321157 in words is "twenty-one trillion, forty billion, three hundred twenty million, three hundred twenty-one thousand, one hundred fifty-seven".