21071751901 has 2 divisors, whose sum is σ = 21071751902. Its totient is φ = 21071751900.

The previous prime is 21071751851. The next prime is 21071751913. The reversal of 21071751901 is 10915717012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16444215225 + 4627536676 = 128235^2 + 68026^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21071751901 is a prime.

It is a super-2 number, since 2×21071751901² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21071751931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10535875950 + 10535875951.

It is an arithmetic number, because the mean of its divisors is an integer number (10535875951).

Almost surely, 2^21071751901 is an apocalyptic number.

It is an amenable number.

21071751901 is a deficient number, since it is larger than the sum of its proper divisors (1).

21071751901 is an equidigital number, since it uses as much as digits as its factorization.

21071751901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4410, while the sum is 34.

The spelling of 21071751901 in words is "twenty-one billion, seventy-one million, seven hundred fifty-one thousand, nine hundred one".