20409493121 has 2 divisors, whose sum is σ = 20409493122. Its totient is φ = 20409493120.

The previous prime is 20409493109. The next prime is 20409493129. The reversal of 20409493121 is 12139490402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10545030721 + 9864462400 = 102689^2 + 99320^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20409493121 is a prime.

It is a super-2 number, since 2×20409493121² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20409493129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10204746560 + 10204746561.

It is an arithmetic number, because the mean of its divisors is an integer number (10204746561).

Almost surely, 2^20409493121 is an apocalyptic number.

It is an amenable number.

20409493121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20409493121 is an equidigital number, since it uses as much as digits as its factorization.

20409493121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 35.

The spelling of 20409493121 in words is "twenty billion, four hundred nine million, four hundred ninety-three thousand, one hundred twenty-one".