821674642 has 4 divisors (see below), whose sum is σ = 1232511966. Its totient is φ = 410837320.

The previous prime is 821674639. The next prime is 821674643. The reversal of 821674642 is 246476128.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 711235561 + 110439081 = 26669^2 + 10509^2 .

It is a junction number, because it is equal to n+sod(n) for n = 821674595 and 821674604.

It is not an unprimeable number, because it can be changed into a prime (821674643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205418659 + ... + 205418662.

Almost surely, 2^821674642 is an apocalyptic number.

821674642 is a deficient number, since it is larger than the sum of its proper divisors (410837324).

821674642 is a wasteful number, since it uses less digits than its factorization.

821674642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410837323.

The product of its digits is 129024, while the sum is 40.

The square root of 821674642 is about 28664.8677303768. The cubic root of 821674642 is about 936.6269032116.

The spelling of 821674642 in words is "eight hundred twenty-one million, six hundred seventy-four thousand, six hundred forty-two".