20311129991 has 2 divisors, whose sum is σ = 20311129992. Its totient is φ = 20311129990.

The previous prime is 20311129987. The next prime is 20311130003. The reversal of 20311129991 is 19992111302.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20311129991 - 2² = 20311129987 is a prime.

It is a super-2 number, since 2×20311129991² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20311129921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155564995 + 10155564996.

It is an arithmetic number, because the mean of its divisors is an integer number (10155564996).

Almost surely, 2^20311129991 is an apocalyptic number.

20311129991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20311129991 is an equidigital number, since it uses as much as digits as its factorization.

20311129991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8748, while the sum is 38.

The spelling of 20311129991 in words is "twenty billion, three hundred eleven million, one hundred twenty-nine thousand, nine hundred ninety-one".