1099209521 has 4 divisors (see below), whose sum is σ = 1099303152. Its totient is φ = 1099115892.

The previous prime is 1099209493. The next prime is 1099209547. The reversal of 1099209521 is 1259029901.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1259029901 = 1117 ⋅1127153.

It is a cyclic number.

It is not a de Polignac number, because 1099209521 - 2⁶ = 1099209457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1099209121) 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, 26171 + ... + 53696.

It is an arithmetic number, because the mean of its divisors is an integer number (274825788).

Almost surely, 2^1099209521 is an apocalyptic number.

It is an amenable number.

1099209521 is a deficient number, since it is larger than the sum of its proper divisors (93631).

1099209521 is an equidigital number, since it uses as much as digits as its factorization.

1099209521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93630.

The product of its (nonzero) digits is 14580, while the sum is 38.

The square root of 1099209521 is about 33154.3288425509. The cubic root of 1099209521 is about 1032.0327847611.

The spelling of 1099209521 in words is "one billion, ninety-nine million, two hundred nine thousand, five hundred twenty-one".