11387981 has 12 divisors (see below), whose sum is σ = 12876864. Its totient is φ = 9987600.

The previous prime is 11387953. The next prime is 11388017. The reversal of 11387981 is 18978311.

11387981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 11387981 - 2⁶ = 11387917 is a prime.

It is a super-2 number, since 2×11387981² = 259372222512722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11387281) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8636 + ... + 9866.

It is an arithmetic number, because the mean of its divisors is an integer number (1073072).

Almost surely, 2^11387981 is an apocalyptic number.

11387981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11387981 is a deficient number, since it is larger than the sum of its proper divisors (1488883).

11387981 is a wasteful number, since it uses less digits than its factorization.

11387981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300 (or 1271 counting only the distinct ones).

The product of its digits is 12096, while the sum is 38.

The square root of 11387981 is about 3374.6082735630. The cubic root of 11387981 is about 224.9825895993.

It can be divided in two parts, 1138 and 7981, that added together give a palindrome (9119).

The spelling of 11387981 in words is "eleven million, three hundred eighty-seven thousand, nine hundred eighty-one".