21000068357 has 2 divisors, whose sum is σ = 21000068358. Its totient is φ = 21000068356.

The previous prime is 21000068339. The next prime is 21000068371. The reversal of 21000068357 is 75386000012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21000067396 + 961 = 144914^2 + 31^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000068357 - 2¹⁴ = 21000051973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000068657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500034178 + 10500034179.

It is an arithmetic number, because the mean of its divisors is an integer number (10500034179).

Almost surely, 2^21000068357 is an apocalyptic number.

It is an amenable number.

21000068357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000068357 is an equidigital number, since it uses as much as digits as its factorization.

21000068357 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 32.

Adding to 21000068357 its reverse (75386000012), we get a palindrome (96386068369).

The spelling of 21000068357 in words is "twenty-one billion, sixty-eight thousand, three hundred fifty-seven".