821630242 has 16 divisors (see below), whose sum is σ = 1317399552. Its totient is φ = 383368480.

The previous prime is 821630207. The next prime is 821630263. The reversal of 821630242 is 242036128.

It is a self number, because there is not a number n which added to its sum of digits gives 821630242.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215938 + ... + 219709.

It is an arithmetic number, because the mean of its divisors is an integer number (82337472).

Almost surely, 2^821630242 is an apocalyptic number.

821630242 is a gapful number since it is divisible by the number (82) formed by its first and last digit.

821630242 is a deficient number, since it is larger than the sum of its proper divisors (495769310).

821630242 is a wasteful number, since it uses less digits than its factorization.

821630242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435713.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 821630242 is about 28664.0932527090. The cubic root of 821630242 is about 936.6100323881.

It can be divided in two parts, 82 and 1630242, that multiplied together give a square (133679844 = 11562²).

The spelling of 821630242 in words is "eight hundred twenty-one million, six hundred thirty thousand, two hundred forty-two".