20190259781 has 2 divisors, whose sum is σ = 20190259782. Its totient is φ = 20190259780.

The previous prime is 20190259777. The next prime is 20190259823. The reversal of 20190259781 is 18795209102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12908368225 + 7281891556 = 113615^2 + 85334^2 .

It is a cyclic number.

It is not a de Polignac number, because 20190259781 - 2² = 20190259777 is a prime.

It is a super-2 number, since 2×20190259781² (a number of 21 digits) contains 22 as substring.

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 (20190259381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10095129890 + 10095129891.

It is an arithmetic number, because the mean of its divisors is an integer number (10095129891).

Almost surely, 2^20190259781 is an apocalyptic number.

It is an amenable number.

20190259781 is a deficient number, since it is larger than the sum of its proper divisors (1).

20190259781 is an equidigital number, since it uses as much as digits as its factorization.

20190259781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 44.

The spelling of 20190259781 in words is "twenty billion, one hundred ninety million, two hundred fifty-nine thousand, seven hundred eighty-one".