21210433357 has 2 divisors, whose sum is σ = 21210433358. Its totient is φ = 21210433356.

The previous prime is 21210433327. The next prime is 21210433393. The reversal of 21210433357 is 75333401212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20456436676 + 753996681 = 143026^2 + 27459^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210433357 - 2²³ = 21202044749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210433327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605216678 + 10605216679.

It is an arithmetic number, because the mean of its divisors is an integer number (10605216679).

Almost surely, 2^21210433357 is an apocalyptic number.

It is an amenable number.

21210433357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210433357 is an equidigital number, since it uses as much as digits as its factorization.

21210433357 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 31.

Adding to 21210433357 its reverse (75333401212), we get a palindrome (96543834569).

The spelling of 21210433357 in words is "twenty-one billion, two hundred ten million, four hundred thirty-three thousand, three hundred fifty-seven".