11973781 has 16 divisors (see below), whose sum is σ = 13478400. Its totient is φ = 10584000.

The previous prime is 11973779. The next prime is 11973791. The reversal of 11973781 is 18737911.

It is a 3-Lehmer number, since φ(11973781) divides (11973781-1)³.

It is a cyclic number.

It is not a de Polignac number, because 11973781 - 2¹ = 11973779 is a prime.

It is a super-2 number, since 2×11973781² = 286742862871922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11973781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11973701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16731 + ... + 17431.

It is an arithmetic number, because the mean of its divisors is an integer number (842400).

Almost surely, 2^11973781 is an apocalyptic number.

11973781 is the 1548-th centered decagonal number.

It is an amenable number.

11973781 is a deficient number, since it is larger than the sum of its proper divisors (1504619).

11973781 is a wasteful number, since it uses less digits than its factorization.

11973781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 780.

The product of its digits is 10584, while the sum is 37.

The square root of 11973781 is about 3460.3151590570. The cubic root of 11973781 is about 228.7759865766.

The spelling of 11973781 in words is "eleven million, nine hundred seventy-three thousand, seven hundred eighty-one".