20689161481 has 2 divisors, whose sum is σ = 20689161482. Its totient is φ = 20689161480.

The previous prime is 20689161433. The next prime is 20689161497. The reversal of 20689161481 is 18416198602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19462761081 + 1226400400 = 139509^2 + 35020^2 .

It is a cyclic number.

It is not a de Polignac number, because 20689161481 - 2²⁷ = 20554943753 is a prime.

It is a super-2 number, since 2×20689161481² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20689161421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10344580740 + 10344580741.

It is an arithmetic number, because the mean of its divisors is an integer number (10344580741).

Almost surely, 2^20689161481 is an apocalyptic number.

It is an amenable number.

20689161481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20689161481 is an equidigital number, since it uses as much as digits as its factorization.

20689161481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 165888, while the sum is 46.

The spelling of 20689161481 in words is "twenty billion, six hundred eighty-nine million, one hundred sixty-one thousand, four hundred eighty-one".