1099651921 has 3 divisors (see below), whose sum is σ = 1099685083. Its totient is φ = 1099618760.

The previous prime is 1099651909. The next prime is 1099651937. The reversal of 1099651921 is 1291569901.

The square root of 1099651921 is 33161.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1291569901 = 317 ⋅4074353.

It can be written as a sum of positive squares in only one way, i.e., 1047234321 + 52417600 = 32361^2 + 7240^2 .

It is not a de Polignac number, because 1099651921 - 2¹⁵ = 1099619153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1099651901) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 16581 + ... + 49741.

Almost surely, 2^1099651921 is an apocalyptic number.

1099651921 is the 33161-st square number.

1099651921 is the 16581-st centered octagonal number.

It is an amenable number.

1099651921 is a deficient number, since it is larger than the sum of its proper divisors (33162).

1099651921 is an frugal number, since it uses more digits than its factorization.

1099651921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66322 (or 33161 counting only the distinct ones).

The product of its (nonzero) digits is 43740, while the sum is 43.

The cubic root of 1099651921 is about 1032.1712206270.

The spelling of 1099651921 in words is "one billion, ninety-nine million, six hundred fifty-one thousand, nine hundred twenty-one".