20396249981 has 2 divisors, whose sum is σ = 20396249982. Its totient is φ = 20396249980.

The previous prime is 20396249917. The next prime is 20396250001. The reversal of 20396249981 is 18994269302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12434257081 + 7961992900 = 111509^2 + 89230^2 .

It is a cyclic number.

It is not a de Polignac number, because 20396249981 - 2⁶ = 20396249917 is a prime.

It is a super-2 number, since 2×20396249981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20396240981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10198124990 + 10198124991.

It is an arithmetic number, because the mean of its divisors is an integer number (10198124991).

Almost surely, 2^20396249981 is an apocalyptic number.

It is an amenable number.

20396249981 is a deficient number, since it is larger than the sum of its proper divisors (1).

20396249981 is an equidigital number, since it uses as much as digits as its factorization.

20396249981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1679616, while the sum is 53.

The spelling of 20396249981 in words is "twenty billion, three hundred ninety-six million, two hundred forty-nine thousand, nine hundred eighty-one".