821397039 has 4 divisors (see below), whose sum is σ = 1095196056. Its totient is φ = 547598024.

The previous prime is 821397023. The next prime is 821397043. The reversal of 821397039 is 930793128.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 821397039 - 2⁴ = 821397023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821397439) 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, 136899504 + ... + 136899509.

It is an arithmetic number, because the mean of its divisors is an integer number (273799014).

Almost surely, 2^821397039 is an apocalyptic number.

821397039 is a deficient number, since it is larger than the sum of its proper divisors (273799017).

821397039 is a wasteful number, since it uses less digits than its factorization.

821397039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273799016.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 821397039 is about 28660.0251046645. The cubic root of 821397039 is about 936.5214114464.

The spelling of 821397039 in words is "eight hundred twenty-one million, three hundred ninety-seven thousand, thirty-nine".