821707313440 has 96 divisors (see below), whose sum is σ = 2213590362480. Its totient is φ = 285552574464.

The previous prime is 821707313437. The next prime is 821707313443. The reversal of 821707313440 is 44313707128.

It is an interprime number because it is at equal distance from previous prime (821707313437) and next prime (821707313443).

It can be written as a sum of positive squares in 8 ways, for example, as 613709292816 + 207998020624 = 783396^2 + 456068^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 821707313393 and 821707313402.

It is not an unprimeable number, because it can be changed into a prime (821707313443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11583805 + ... + 11654524.

Almost surely, 2^821707313440 is an apocalyptic number.

821707313440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

821707313440 is an abundant number, since it is smaller than the sum of its proper divisors (1391883049040).

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

821707313440 is a wasteful number, since it uses less digits than its factorization.

821707313440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23238374 (or 23238366 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 40.

The spelling of 821707313440 in words is "eight hundred twenty-one billion, seven hundred seven million, three hundred thirteen thousand, four hundred forty".