20012420261 has 2 divisors, whose sum is σ = 20012420262. Its totient is φ = 20012420260.

The previous prime is 20012420237. The next prime is 20012420279. The reversal of 20012420261 is 16202421002.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14585151361 + 5427268900 = 120769^2 + 73670^2 .

It is a cyclic number.

It is not a de Polignac number, because 20012420261 - 2³⁴ = 2832551077 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20012420231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10006210130 + 10006210131.

It is an arithmetic number, because the mean of its divisors is an integer number (10006210131).

Almost surely, 2^20012420261 is an apocalyptic number.

It is an amenable number.

20012420261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20012420261 is an equidigital number, since it uses as much as digits as its factorization.

20012420261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 20012420261 its reverse (16202421002), we get a palindrome (36214841263).

The spelling of 20012420261 in words is "twenty billion, twelve million, four hundred twenty thousand, two hundred sixty-one".