1098921 has 4 divisors (see below), whose sum is σ = 1465232. Its totient is φ = 732612.

The previous prime is 1098847. The next prime is 1098953. The reversal of 1098921 is 1298901.

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.

It is not a de Polignac number, because 1098921 - 2¹⁰ = 1097897 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1098121) 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, 183151 + ... + 183156.

It is an arithmetic number, because the mean of its divisors is an integer number (366308).

2^1098921 is an apocalyptic number.

It is an amenable number.

1098921 is a deficient number, since it is larger than the sum of its proper divisors (366311).

1098921 is an equidigital number, since it uses as much as digits as its factorization.

1098921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366310.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 1098921 is about 1048.2943288981. The cubic root of 1098921 is about 103.1942480719.

The spelling of 1098921 in words is "one million, ninety-eight thousand, nine hundred twenty-one".