821872440 has 64 divisors (see below), whose sum is σ = 2739578400. Its totient is φ = 219165696.

The previous prime is 821872439. The next prime is 821872477. The reversal of 821872440 is 44278128.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 821872395 and 821872404.

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, 379417 + ... + 381576.

Almost surely, 2^821872440 is an apocalyptic number.

It is an amenable number.

821872440 is an abundant number, since it is smaller than the sum of its proper divisors (1917705960).

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

821872440 is a wasteful number, since it uses less digits than its factorization.

821872440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761013 (or 761003 counting only the distinct ones).

The product of its (nonzero) digits is 28672, while the sum is 36.

The square root of 821872440 is about 28668.3177043928. The cubic root of 821872440 is about 936.7020538267.

The spelling of 821872440 in words is "eight hundred twenty-one million, eight hundred seventy-two thousand, four hundred forty".