20461564421 has 2 divisors, whose sum is σ = 20461564422.
Its totient is φ = 20461564420.
The previous prime is 20461564369. The next prime is 20461564471. The reversal of 20461564421 is 12446516402.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 20437847521 + 23716900 = 142961^2 + 4870^2
It is a cyclic number.
It is not a de Polignac number, because 20461564421 - 234 = 3281695237 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (20461564471) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10230782210 + 10230782211.
It is an arithmetic number, because the mean of its divisors is an integer number (10230782211).
Almost surely, 220461564421 is an apocalyptic number.
It is an amenable number.
20461564421 is a deficient number, since it is larger than the sum of its proper divisors (1).
20461564421 is an equidigital number, since it uses as much as digits as its factorization.
20461564421 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 46080, while the sum is 35.
The spelling of 20461564421 in words is "twenty billion, four hundred sixty-one million, five hundred sixty-four thousand, four hundred twenty-one".