821504240 has 40 divisors (see below), whose sum is σ = 1946045088. Its totient is φ = 322400000.

The previous prime is 821504231. The next prime is 821504267. The reversal of 821504240 is 42405128.

It is a happy number.

821504240 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92636 + ... + 101115.

Almost surely, 2^821504240 is an apocalyptic number.

821504240 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

821504240 is an abundant number, since it is smaller than the sum of its proper divisors (1124540848).

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

821504240 is a wasteful number, since it uses less digits than its factorization.

821504240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193817 (or 193811 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 821504240 is about 28661.8952618280. The cubic root of 821504240 is about 936.5621516568.

Adding to 821504240 its reverse (42405128), we get a palindrome (863909368).

The spelling of 821504240 in words is "eight hundred twenty-one million, five hundred four thousand, two hundred forty".