20012021261 has 2 divisors, whose sum is σ = 20012021262. Its totient is φ = 20012021260.

The previous prime is 20012021233. The next prime is 20012021273. The reversal of 20012021261 is 16212021002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19992263236 + 19758025 = 141394^2 + 4445^2 .

It is a cyclic number.

It is not a de Polignac number, because 20012021261 - 2¹⁴ = 20012004877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20012027261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10006010630 + 10006010631.

It is an arithmetic number, because the mean of its divisors is an integer number (10006010631).

Almost surely, 2^20012021261 is an apocalyptic number.

It is an amenable number.

20012021261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20012021261 is an equidigital number, since it uses as much as digits as its factorization.

20012021261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 20012021261 its reverse (16212021002), we get a palindrome (36224042263).

The spelling of 20012021261 in words is "twenty billion, twelve million, twenty-one thousand, two hundred sixty-one".