7821990002 has 4 divisors (see below), whose sum is σ = 11732985006. Its totient is φ = 3910995000.

The previous prime is 7821989999. The next prime is 7821990019. The reversal of 7821990002 is 2000991287.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2000991287 = 1009 ⋅1983143.

It can be written as a sum of positive squares in only one way, i.e., 5034044401 + 2787945601 = 70951^2 + 52801^2 .

It is a super-2 number, since 2×7821990002² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1955497499 + ... + 1955497502.

Almost surely, 2^7821990002 is an apocalyptic number.

7821990002 is a deficient number, since it is larger than the sum of its proper divisors (3910995004).

7821990002 is a wasteful number, since it uses less digits than its factorization.

7821990002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3910995003.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 7821990002 is about 88442.0149137275. The cubic root of 7821990002 is about 1985.0544266177.

The spelling of 7821990002 in words is "seven billion, eight hundred twenty-one million, nine hundred ninety thousand, two".