21604212403157 has 2 divisors, whose sum is σ = 21604212403158. Its totient is φ = 21604212403156.

The previous prime is 21604212403139. The next prime is 21604212403199. The reversal of 21604212403157 is 75130421240612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13853812529041 + 7750399874116 = 3722071^2 + 2783954^2 .

It is a cyclic number.

It is not a de Polignac number, because 21604212403157 - 2⁶ = 21604212403093 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21604212403157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21604212403117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802106201578 + 10802106201579.

It is an arithmetic number, because the mean of its divisors is an integer number (10802106201579).

Almost surely, 2^{21604212403157} is an apocalyptic number.

It is an amenable number.

21604212403157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21604212403157 is an equidigital number, since it uses as much as digits as its factorization.

21604212403157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 38.

Adding to 21604212403157 its reverse (75130421240612), we get a palindrome (96734633643769).

The spelling of 21604212403157 in words is "twenty-one trillion, six hundred four billion, two hundred twelve million, four hundred three thousand, one hundred fifty-seven".