821644494 has 32 divisors (see below), whose sum is σ = 1810442880. Its totient is φ = 246516000.

The previous prime is 821644487. The next prime is 821644511. The reversal of 821644494 is 494446128.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54964 + ... + 68295.

It is an arithmetic number, because the mean of its divisors is an integer number (56576340).

Almost surely, 2^821644494 is an apocalyptic number.

821644494 is an abundant number, since it is smaller than the sum of its proper divisors (988798386).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821644494 is a wasteful number, since it uses less digits than its factorization.

821644494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123376.

The product of its digits is 221184, while the sum is 42.

The square root of 821644494 is about 28664.3418553435. The cubic root of 821644494 is about 936.6154478367.

The spelling of 821644494 in words is "eight hundred twenty-one million, six hundred forty-four thousand, four hundred ninety-four".