1097309821 has 4 divisors (see below), whose sum is σ = 1132706944. Its totient is φ = 1061912700.

The previous prime is 1097309803. The next prime is 1097309839. The reversal of 1097309821 is 1289037901.

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: 1289037901 = 593 ⋅2173757.

It is an interprime number because it is at equal distance from previous prime (1097309803) and next prime (1097309839).

It is a cyclic number.

It is not a de Polignac number, because 1097309821 - 2²¹ = 1095212669 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 (1097309021) 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, 17698515 + ... + 17698576.

It is an arithmetic number, because the mean of its divisors is an integer number (283176736).

Almost surely, 2^1097309821 is an apocalyptic number.

It is an amenable number.

1097309821 is a deficient number, since it is larger than the sum of its proper divisors (35397123).

1097309821 is an equidigital number, since it uses as much as digits as its factorization.

1097309821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35397122.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 1097309821 is about 33125.6671027166. The cubic root of 1097309821 is about 1031.4379078167.

The spelling of 1097309821 in words is "one billion, ninety-seven million, three hundred nine thousand, eight hundred twenty-one".