11613781 has 4 divisors (see below), whose sum is σ = 12118752. Its totient is φ = 11108812.

The previous prime is 11613773. The next prime is 11613793. The reversal of 11613781 is 18731611.

11613781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is not a de Polignac number, because 11613781 - 2³ = 11613773 is a prime.

It is a super-2 number, since 2×11613781² = 269759818231922, 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 (11613751) 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, 252451 + ... + 252496.

It is an arithmetic number, because the mean of its divisors is an integer number (3029688).

Almost surely, 2^11613781 is an apocalyptic number.

It is an amenable number.

11613781 is a deficient number, since it is larger than the sum of its proper divisors (504971).

11613781 is an equidigital number, since it uses as much as digits as its factorization.

11613781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504970.

The product of its digits is 1008, while the sum is 28.

The square root of 11613781 is about 3407.8997931277. The cubic root of 11613781 is about 226.4598476322.

The spelling of 11613781 in words is "eleven million, six hundred thirteen thousand, seven hundred eighty-one".