821242 has 4 divisors (see below), whose sum is σ = 1231866. Its totient is φ = 410620.

The previous prime is 821209. The next prime is 821263. The reversal of 821242 is 242128.

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., 519841 + 301401 = 721^2 + 549^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205309 + ... + 205312.

2⁸²¹²⁴² is an apocalyptic number.

821242 is a deficient number, since it is larger than the sum of its proper divisors (410624).

821242 is a wasteful number, since it uses less digits than its factorization.

821242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410623.

The product of its digits is 256, while the sum is 19.

The square root of 821242 is about 906.2240341108. The cubic root of 821242 is about 93.6462484816.

The spelling of 821242 in words is "eight hundred twenty-one thousand, two hundred forty-two".