821500720 has 40 divisors (see below), whose sum is σ = 2010518640. Its totient is φ = 311304960.

The previous prime is 821500633. The next prime is 821500753. The reversal of 821500720 is 27005128.

821500720 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 an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 268711 + ... + 271750.

It is an arithmetic number, because the mean of its divisors is an integer number (50262966).

Almost surely, 2^821500720 is an apocalyptic number.

821500720 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

821500720 is an abundant number, since it is smaller than the sum of its proper divisors (1189017920).

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

821500720 is a wasteful number, since it uses less digits than its factorization.

821500720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540493 (or 540487 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 821500720 is about 28661.8338561928. The cubic root of 821500720 is about 936.5608139873.

Adding to 821500720 its reverse (27005128), we get a palindrome (848505848).

The spelling of 821500720 in words is "eight hundred twenty-one million, five hundred thousand, seven hundred twenty".