20149230781 has 2 divisors, whose sum is σ = 20149230782. Its totient is φ = 20149230780.

The previous prime is 20149230743. The next prime is 20149230817. The reversal of 20149230781 is 18703294102.

Together with next prime (20149230817) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10310574681 + 9838656100 = 101541^2 + 99190^2 .

It is a cyclic number.

It is not a de Polignac number, because 20149230781 - 2¹⁷ = 20149099709 is a prime.

It is a super-2 number, since 2×20149230781² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20149230781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20149230481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10074615390 + 10074615391.

It is an arithmetic number, because the mean of its divisors is an integer number (10074615391).

Almost surely, 2^20149230781 is an apocalyptic number.

It is an amenable number.

20149230781 is a deficient number, since it is larger than the sum of its proper divisors (1).

20149230781 is an equidigital number, since it uses as much as digits as its factorization.

20149230781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 37.

The spelling of 20149230781 in words is "twenty billion, one hundred forty-nine million, two hundred thirty thousand, seven hundred eighty-one".