20624406581 has 2 divisors, whose sum is σ = 20624406582. Its totient is φ = 20624406580.

The previous prime is 20624406527. The next prime is 20624406599. The reversal of 20624406581 is 18560442602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14792640625 + 5831765956 = 121625^2 + 76366^2 .

It is a cyclic number.

It is not a de Polignac number, because 20624406581 - 2¹⁴ = 20624390197 is a prime.

It is a super-2 number, since 2×20624406581² (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 (20624400581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10312203290 + 10312203291.

It is an arithmetic number, because the mean of its divisors is an integer number (10312203291).

Almost surely, 2^20624406581 is an apocalyptic number.

It is an amenable number.

20624406581 is a deficient number, since it is larger than the sum of its proper divisors (1).

20624406581 is an equidigital number, since it uses as much as digits as its factorization.

20624406581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 92160, while the sum is 38.

The spelling of 20624406581 in words is "twenty billion, six hundred twenty-four million, four hundred six thousand, five hundred eighty-one".