20751165121 has 2 divisors, whose sum is σ = 20751165122. Its totient is φ = 20751165120.

The previous prime is 20751165103. The next prime is 20751165157. The reversal of 20751165121 is 12156115702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20487914496 + 263250625 = 143136^2 + 16225^2 .

It is a cyclic number.

It is not a de Polignac number, because 20751165121 - 2¹¹ = 20751163073 is a prime.

It is a super-2 number, since 2×20751165121² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20751162121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10375582560 + 10375582561.

It is an arithmetic number, because the mean of its divisors is an integer number (10375582561).

Almost surely, 2^20751165121 is an apocalyptic number.

It is an amenable number.

20751165121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20751165121 is an equidigital number, since it uses as much as digits as its factorization.

20751165121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4200, while the sum is 31.

The spelling of 20751165121 in words is "twenty billion, seven hundred fifty-one million, one hundred sixty-five thousand, one hundred twenty-one".