20451722261 has 2 divisors, whose sum is σ = 20451722262. Its totient is φ = 20451722260.

The previous prime is 20451722243. The next prime is 20451722293. The reversal of 20451722261 is 16222715402.

It is an a-pointer prime, because the next prime (20451722293) can be obtained adding 20451722261 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15975443236 + 4476279025 = 126394^2 + 66905^2 .

It is a cyclic number.

It is not a de Polignac number, because 20451722261 - 2⁶ = 20451722197 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 (20451722231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10225861130 + 10225861131.

It is an arithmetic number, because the mean of its divisors is an integer number (10225861131).

Almost surely, 2^20451722261 is an apocalyptic number.

It is an amenable number.

20451722261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20451722261 is an equidigital number, since it uses as much as digits as its factorization.

20451722261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13440, while the sum is 32.

The spelling of 20451722261 in words is "twenty billion, four hundred fifty-one million, seven hundred twenty-two thousand, two hundred sixty-one".