20451722197 has 2 divisors, whose sum is σ = 20451722198. Its totient is φ = 20451722196.

The previous prime is 20451722167. The next prime is 20451722231. The reversal of 20451722197 is 79122715402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18909275121 + 1542447076 = 137511^2 + 39274^2 .

It is a cyclic number.

It is not a de Polignac number, because 20451722197 - 2¹⁵ = 20451689429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20451722147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10225861098 + 10225861099.

It is an arithmetic number, because the mean of its divisors is an integer number (10225861099).

Almost surely, 2^20451722197 is an apocalyptic number.

It is an amenable number.

20451722197 is a deficient number, since it is larger than the sum of its proper divisors (1).

20451722197 is an equidigital number, since it uses as much as digits as its factorization.

20451722197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70560, while the sum is 40.

The spelling of 20451722197 in words is "twenty billion, four hundred fifty-one million, seven hundred twenty-two thousand, one hundred ninety-seven".