821970240 has 336 divisors, whose sum is σ = 3245461632. Its totient is φ = 171638784.

The previous prime is 821970223. The next prime is 821970277. The reversal of 821970240 is 42079128.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (336).

It is a congruent number.

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 47 ways as a sum of consecutive naturals, for example, 8473872 + ... + 8473968.

It is an arithmetic number, because the mean of its divisors is an integer number (9659112).

Almost surely, 2^821970240 is an apocalyptic number.

821970240 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821970240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1622730816).

821970240 is an abundant number, since it is smaller than the sum of its proper divisors (2423491392).

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

821970240 is a wasteful number, since it uses less digits than its factorization.

821970240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 821970240 is about 28670.0233693661. The cubic root of 821970240 is about 936.7392071297.

The spelling of 821970240 in words is "eight hundred twenty-one million, nine hundred seventy thousand, two hundred forty".