1091388 has 24 divisors (see below), whose sum is σ = 2574208. Its totient is φ = 359856.

The previous prime is 1091381. The next prime is 1091393. The reversal of 1091388 is 8831901.

It is a super-2 number, since 2×1091388² = 2382255533088, which contains 22 as substring.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091381) 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, 795 + ... + 1677.

2^1091388 is an apocalyptic number.

It is an amenable number.

1091388 is an abundant number, since it is smaller than the sum of its proper divisors (1482820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1091388 is a wasteful number, since it uses less digits than its factorization.

1091388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 993 (or 991 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 30.

The square root of 1091388 is about 1044.6951708513. The cubic root of 1091388 is about 102.9579116066.

The spelling of 1091388 in words is "one million, ninety-one thousand, three hundred eighty-eight".