20624431081 has 2 divisors, whose sum is σ = 20624431082. Its totient is φ = 20624431080.

The previous prime is 20624431031. The next prime is 20624431103. The reversal of 20624431081 is 18013442602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12509304025 + 8115127056 = 111845^2 + 90084^2 .

It is a cyclic number.

It is not a de Polignac number, because 20624431081 - 2²⁷ = 20490213353 is a prime.

It is a super-2 number, since 2×20624431081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20624431031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10312215540 + 10312215541.

It is an arithmetic number, because the mean of its divisors is an integer number (10312215541).

Almost surely, 2^20624431081 is an apocalyptic number.

It is an amenable number.

20624431081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20624431081 is an equidigital number, since it uses as much as digits as its factorization.

20624431081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 31.

Adding to 20624431081 its reverse (18013442602), we get a palindrome (38637873683).

The spelling of 20624431081 in words is "twenty billion, six hundred twenty-four million, four hundred thirty-one thousand, eighty-one".