20121025109 has 2 divisors, whose sum is σ = 20121025110. Its totient is φ = 20121025108.

The previous prime is 20121025081. The next prime is 20121025139. The reversal of 20121025109 is 90152012102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20115748900 + 5276209 = 141830^2 + 2297^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121025109 - 2²⁴ = 20104247893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20121025139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060512554 + 10060512555.

It is an arithmetic number, because the mean of its divisors is an integer number (10060512555).

Almost surely, 2^20121025109 is an apocalyptic number.

It is an amenable number.

20121025109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121025109 is an equidigital number, since it uses as much as digits as its factorization.

20121025109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 23.

The spelling of 20121025109 in words is "twenty billion, one hundred twenty-one million, twenty-five thousand, one hundred nine".