11505981 has 8 divisors (see below), whose sum is σ = 15419200. Its totient is φ = 7631712.

The previous prime is 11505973. The next prime is 11505997. The reversal of 11505981 is 18950511.

11505981 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 11505981 - 2³ = 11505973 is a prime.

It is a super-2 number, since 2×11505981² = 264775197544722, 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 (11505961) 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, 9040 + ... + 10233.

It is an arithmetic number, because the mean of its divisors is an integer number (1927400).

Almost surely, 2^11505981 is an apocalyptic number.

It is an amenable number.

11505981 is a deficient number, since it is larger than the sum of its proper divisors (3913219).

11505981 is a wasteful number, since it uses less digits than its factorization.

11505981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19475.

The product of its (nonzero) digits is 1800, while the sum is 30.

The square root of 11505981 is about 3392.0467272725. The cubic root of 11505981 is about 225.7569959655.

The spelling of 11505981 in words is "eleven million, five hundred five thousand, nine hundred eighty-one".