7800021 has 12 divisors (see below), whose sum is σ = 11295648. Its totient is φ = 5186664.

The previous prime is 7800017. The next prime is 7800029. The reversal of 7800021 is 1200087.

7800021 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 7800021 - 2² = 7800017 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 7799967 and 7800003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7800029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3666 + ... + 5388.

It is an arithmetic number, because the mean of its divisors is an integer number (941304).

Almost surely, 2^7800021 is an apocalyptic number.

It is an amenable number.

7800021 is a deficient number, since it is larger than the sum of its proper divisors (3495627).

7800021 is a wasteful number, since it uses less digits than its factorization.

7800021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2232 (or 2229 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 7800021 is about 2792.8517683543. The cubic root of 7800021 is about 198.3194262467.

The spelling of 7800021 in words is "seven million, eight hundred thousand, twenty-one".