20121089881 has 2 divisors, whose sum is σ = 20121089882. Its totient is φ = 20121089880.

The previous prime is 20121089869. The next prime is 20121089887. The reversal of 20121089881 is 18898012102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16546963225 + 3574126656 = 128635^2 + 59784^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121089881 - 2¹⁵ = 20121057113 is a prime.

It is a super-2 number, since 2×20121089881² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20121089887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060544940 + 10060544941.

It is an arithmetic number, because the mean of its divisors is an integer number (10060544941).

Almost surely, 2^20121089881 is an apocalyptic number.

It is an amenable number.

20121089881 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121089881 is an equidigital number, since it uses as much as digits as its factorization.

20121089881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18432, while the sum is 40.

The spelling of 20121089881 in words is "twenty billion, one hundred twenty-one million, eighty-nine thousand, eight hundred eighty-one".