21735143315257 has 2 divisors, whose sum is σ = 21735143315258. Its totient is φ = 21735143315256.

The previous prime is 21735143315203. The next prime is 21735143315269. The reversal of 21735143315257 is 75251334153712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18984285553216 + 2750857762041 = 4357096^2 + 1658571^2 .

It is a cyclic number.

It is not a de Polignac number, because 21735143315257 - 2⁷ = 21735143315129 is a prime.

It is a super-2 number, since 2×21735143315257² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21735143315257.

It is not a weakly prime, because it can be changed into another prime (21735143315287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10867571657628 + 10867571657629.

It is an arithmetic number, because the mean of its divisors is an integer number (10867571657629).

Almost surely, 2^{21735143315257} is an apocalyptic number.

It is an amenable number.

21735143315257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21735143315257 is an equidigital number, since it uses as much as digits as its factorization.

21735143315257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2646000, while the sum is 49.

Adding to 21735143315257 its reverse (75251334153712), we get a palindrome (96986477468969).

The spelling of 21735143315257 in words is "twenty-one trillion, seven hundred thirty-five billion, one hundred forty-three million, three hundred fifteen thousand, two hundred fifty-seven".