2123949815081 has 2 divisors, whose sum is σ = 2123949815082. Its totient is φ = 2123949815080.

The previous prime is 2123949815069. The next prime is 2123949815101. The reversal of 2123949815081 is 1805189493212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1962815010025 + 161134805056 = 1401005^2 + 401416^2 .

It is a cyclic number.

It is not a de Polignac number, because 2123949815081 - 2¹⁸ = 2123949552937 is a prime.

It is a super-2 number, since 2×2123949815081² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2123949812081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1061974907540 + 1061974907541.

It is an arithmetic number, because the mean of its divisors is an integer number (1061974907541).

Almost surely, 2^{2123949815081} is an apocalyptic number.

It is an amenable number.

2123949815081 is a deficient number, since it is larger than the sum of its proper divisors (1).

2123949815081 is an equidigital number, since it uses as much as digits as its factorization.

2123949815081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1244160, while the sum is 53.

The spelling of 2123949815081 in words is "two trillion, one hundred twenty-three billion, nine hundred forty-nine million, eight hundred fifteen thousand, eighty-one".