1098661 has 4 divisors (see below), whose sum is σ = 1100800. Its totient is φ = 1096524.

The previous prime is 1098649. The next prime is 1098667. The reversal of 1098661 is 1668901.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1668901 = 13 ⋅128377.

It is a cyclic number.

It is not a de Polignac number, because 1098661 - 2⁷ = 1098533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1098667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 220 + ... + 1498.

It is an arithmetic number, because the mean of its divisors is an integer number (275200).

2^1098661 is an apocalyptic number.

It is an amenable number.

1098661 is a deficient number, since it is larger than the sum of its proper divisors (2139).

1098661 is an equidigital number, since it uses as much as digits as its factorization.

1098661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2138.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 1098661 is about 1048.1703105889. The cubic root of 1098661 is about 103.1861089910.

The spelling of 1098661 in words is "one million, ninety-eight thousand, six hundred sixty-one".