18105958957621 has 2 divisors, whose sum is σ = 18105958957622. Its totient is φ = 18105958957620.

The previous prime is 18105958957577. The next prime is 18105958957631. The reversal of 18105958957621 is 12675985950181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17811311919025 + 294647038596 = 4220345^2 + 542814^2 .

It is a cyclic number.

It is not a de Polignac number, because 18105958957621 - 2⁹ = 18105958957109 is a prime.

It is a super-2 number, since 2×18105958957621² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18105958957631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9052979478810 + 9052979478811.

It is an arithmetic number, because the mean of its divisors is an integer number (9052979478811).

Almost surely, 2^{18105958957621} is an apocalyptic number.

It is an amenable number.

18105958957621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18105958957621 is an equidigital number, since it uses as much as digits as its factorization.

18105958957621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432000, while the sum is 67.

The spelling of 18105958957621 in words is "eighteen trillion, one hundred five billion, nine hundred fifty-eight million, nine hundred fifty-seven thousand, six hundred twenty-one".