1091421 has 8 divisors (see below), whose sum is σ = 1616960. Its totient is φ = 727596.

The previous prime is 1091413. The next prime is 1091443. The reversal of 1091421 is 1241901.

It is not a de Polignac number, because 1091421 - 2³ = 1091413 is a prime.

It is an Ulam number.

It is a Duffinian number.

1091421 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1091394 and 1091403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091401) 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 7 ways as a sum of consecutive naturals, for example, 20185 + ... + 20238.

It is an arithmetic number, because the mean of its divisors is an integer number (202120).

2^1091421 is an apocalyptic number.

It is an amenable number.

1091421 is a deficient number, since it is larger than the sum of its proper divisors (525539).

1091421 is an equidigital number, since it uses as much as digits as its factorization.

1091421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40432 (or 40426 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 1091421 is about 1044.7109648128. The cubic root of 1091421 is about 102.9589492995.

The spelling of 1091421 in words is "one million, ninety-one thousand, four hundred twenty-one".