9781239013 has 16 divisors (see below), whose sum is σ = 12095526016. Its totient is φ = 7702309440.

The previous prime is 9781238977. The next prime is 9781239019. The reversal of 9781239013 is 3109321879.

It is a de Polignac number, because none of the positive numbers 2^k-9781239013 is a prime.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 235506 + ... + 273907.

It is an arithmetic number, because the mean of its divisors is an integer number (755970376).

Almost surely, 2^9781239013 is an apocalyptic number.

It is an amenable number.

9781239013 is a deficient number, since it is larger than the sum of its proper divisors (2314287003).

9781239013 is a wasteful number, since it uses less digits than its factorization.

9781239013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509644.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 9781239013 is about 98900.1466783543. The cubic root of 9781239013 is about 2138.6085091121.

The spelling of 9781239013 in words is "nine billion, seven hundred eighty-one million, two hundred thirty-nine thousand, thirteen".