821409742 has 4 divisors (see below), whose sum is σ = 1232114616. Its totient is φ = 410704870.

The previous prime is 821409739. The next prime is 821409761. The reversal of 821409742 is 247904128.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205352434 + ... + 205352437.

It is an arithmetic number, because the mean of its divisors is an integer number (308028654).

Almost surely, 2^821409742 is an apocalyptic number.

821409742 is a deficient number, since it is larger than the sum of its proper divisors (410704874).

821409742 is a wasteful number, since it uses less digits than its factorization.

821409742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410704873.

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 821409742 is about 28660.2467191055. The cubic root of 821409742 is about 936.5262392254.

The spelling of 821409742 in words is "eight hundred twenty-one million, four hundred nine thousand, seven hundred forty-two".