9781239012 has 12 divisors (see below), whose sum is σ = 22822891056. Its totient is φ = 3260413000.

The previous prime is 9781238977. The next prime is 9781239019. The reversal of 9781239012 is 2109321879.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×9781239012² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (9781239019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 407551614 + ... + 407551637.

It is an arithmetic number, because the mean of its divisors is an integer number (1901907588).

Almost surely, 2^9781239012 is an apocalyptic number.

It is an amenable number.

9781239012 is an abundant number, since it is smaller than the sum of its proper divisors (13041652044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9781239012 is a wasteful number, since it uses less digits than its factorization.

9781239012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815103258 (or 815103256 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 9781239012 is about 98900.1466732987. The cubic root of 9781239012 is about 2138.6085090392.

The spelling of 9781239012 in words is "nine billion, seven hundred eighty-one million, two hundred thirty-nine thousand, twelve".