9429901781 has 2 divisors, whose sum is σ = 9429901782. Its totient is φ = 9429901780.

The previous prime is 9429901777. The next prime is 9429901847. The reversal of 9429901781 is 1871099249.

9429901781 = 68665² + 68666².

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4715019556 + 4714882225 = 68666^2 + 68665^2 .

It is an emirp because it is prime and its reverse (1871099249) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9429901781 - 2² = 9429901777 is a prime.

It is a super-2 number, since 2×9429901781² (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 (9429901681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4714950890 + 4714950891.

It is an arithmetic number, because the mean of its divisors is an integer number (4714950891).

Almost surely, 2^9429901781 is an apocalyptic number.

9429901781 is the 68666-th centered square number.

It is an amenable number.

9429901781 is a deficient number, since it is larger than the sum of its proper divisors (1).

9429901781 is an equidigital number, since it uses as much as digits as its factorization.

9429901781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 326592, while the sum is 50.

The square root of 9429901781 is about 97107.6813697042. The cubic root of 9429901781 is about 2112.6897393667.

The spelling of 9429901781 in words is "nine billion, four hundred twenty-nine million, nine hundred one thousand, seven hundred eighty-one".