20335186721 has 2 divisors, whose sum is σ = 20335186722. Its totient is φ = 20335186720.

The previous prime is 20335186661. The next prime is 20335186727. The reversal of 20335186721 is 12768153302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14075212321 + 6259974400 = 118639^2 + 79120^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20335186721 is a prime.

It is not a weakly prime, because it can be changed into another prime (20335186727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10167593360 + 10167593361.

It is an arithmetic number, because the mean of its divisors is an integer number (10167593361).

Almost surely, 2^20335186721 is an apocalyptic number.

It is an amenable number.

20335186721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20335186721 is an equidigital number, since it uses as much as digits as its factorization.

20335186721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 38.

The spelling of 20335186721 in words is "twenty billion, three hundred thirty-five million, one hundred eighty-six thousand, seven hundred twenty-one".