821792109 has 4 divisors (see below), whose sum is σ = 1095722816. Its totient is φ = 547861404.

The previous prime is 821792107. The next prime is 821792141. The reversal of 821792109 is 901297128.

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 821792109 - 2¹ = 821792107 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 (821792107) 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, 136965349 + ... + 136965354.

It is an arithmetic number, because the mean of its divisors is an integer number (273930704).

Almost surely, 2^821792109 is an apocalyptic number.

It is an amenable number.

821792109 is a deficient number, since it is larger than the sum of its proper divisors (273930707).

821792109 is a wasteful number, since it uses less digits than its factorization.

821792109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273930706.

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 821792109 is about 28666.9166287552. The cubic root of 821792109 is about 936.6715346282.

The spelling of 821792109 in words is "eight hundred twenty-one million, seven hundred ninety-two thousand, one hundred nine".