1091621 has 8 divisors (see below), whose sum is σ = 1166040. Its totient is φ = 1018368.

The previous prime is 1091617. The next prime is 1091627. The reversal of 1091621 is 1261901.

It can be written as a sum of positive squares in 4 ways, for example, as 429025 + 662596 = 655^2 + 814^2 .

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

It is not a de Polignac number, because 1091621 - 2² = 1091617 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1091593 and 1091602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2465 + ... + 2873.

It is an arithmetic number, because the mean of its divisors is an integer number (145755).

2^1091621 is an apocalyptic number.

It is an amenable number.

1091621 is a deficient number, since it is larger than the sum of its proper divisors (74419).

1091621 is a wasteful number, since it uses less digits than its factorization.

1091621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 1091621 is about 1044.8066806831. The cubic root of 1091621 is about 102.9652379001.

The spelling of 1091621 in words is "one million, ninety-one thousand, six hundred twenty-one".