12309781 has 8 divisors (see below), whose sum is σ = 13463424. Its totient is φ = 11161920.

The previous prime is 12309769. The next prime is 12309797. The reversal of 12309781 is 18790321.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 12309781 - 2⁵ = 12309749 is a prime.

It is a super-2 number, since 2×12309781² = 303061416535922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12309721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3885 + ... + 6301.

It is an arithmetic number, because the mean of its divisors is an integer number (1682928).

Almost surely, 2^12309781 is an apocalyptic number.

12309781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12309781 is a deficient number, since it is larger than the sum of its proper divisors (1153643).

12309781 is a wasteful number, since it uses less digits than its factorization.

12309781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2891.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 12309781 is about 3508.5297490544. The cubic root of 12309781 is about 230.8961946844.

It can be divided in two parts, 1230 and 9781, that added together give a palindrome (11011).

The spelling of 12309781 in words is "twelve million, three hundred nine thousand, seven hundred eighty-one".