7821428556 has 12 divisors (see below), whose sum is σ = 18249999992. Its totient is φ = 2607142848.

The previous prime is 7821428521. The next prime is 7821428569. The reversal of 7821428556 is 6558241287.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×7821428556² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 325892845 + ... + 325892868.

Almost surely, 2^7821428556 is an apocalyptic number.

It is an amenable number.

7821428556 is an abundant number, since it is smaller than the sum of its proper divisors (10428571436).

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

7821428556 is a wasteful number, since it uses less digits than its factorization.

7821428556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 651785720 (or 651785718 counting only the distinct ones).

The product of its digits is 1075200, while the sum is 48.

The square root of 7821428556 is about 88438.8407658083. The cubic root of 7821428556 is about 1985.0069311367.

The spelling of 7821428556 in words is "seven billion, eight hundred twenty-one million, four hundred twenty-eight thousand, five hundred fifty-six".