11139781 has 4 divisors (see below), whose sum is σ = 11146464. Its totient is φ = 11133100.

The previous prime is 11139773. The next prime is 11139787. The reversal of 11139781 is 18793111.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18793111 = 53 ⋅354587.

It is a cyclic number.

It is not a de Polignac number, because 11139781 - 2³ = 11139773 is a prime.

It is a super-2 number, since 2×11139781² = 248189441455922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11139787) 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, 1446 + ... + 4936.

It is an arithmetic number, because the mean of its divisors is an integer number (2786616).

Almost surely, 2^11139781 is an apocalyptic number.

It is an amenable number.

11139781 is a deficient number, since it is larger than the sum of its proper divisors (6683).

11139781 is an equidigital number, since it uses as much as digits as its factorization.

11139781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6682.

The product of its digits is 1512, while the sum is 31.

The square root of 11139781 is about 3337.6310461164. The cubic root of 11139781 is about 223.3360775386.

The spelling of 11139781 in words is "eleven million, one hundred thirty-nine thousand, seven hundred eighty-one".