11421891 has 20 divisors (see below), whose sum is σ = 18376512. Its totient is φ = 7028208.

The previous prime is 11421889. The next prime is 11421901. The reversal of 11421891 is 19812411.

It is not a de Polignac number, because 11421891 - 2¹ = 11421889 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (11421191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4371 + ... + 6476.

Almost surely, 2^11421891 is an apocalyptic number.

11421891 is a deficient number, since it is larger than the sum of its proper divisors (6954621).

11421891 is a wasteful number, since it uses less digits than its factorization.

11421891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10872 (or 10863 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The square root of 11421891 is about 3379.6288257736. The cubic root of 11421891 is about 225.2056785930.

The spelling of 11421891 in words is "eleven million, four hundred twenty-one thousand, eight hundred ninety-one".