7821198 has 144 divisors (see below), whose sum is σ = 23237760. Its totient is φ = 1924560.

The previous prime is 7821197. The next prime is 7821211. The reversal of 7821198 is 8911287.

It is a super-2 number, since 2×7821198² = 122342276310408, which contains 22 as substring.

It is an Ulam number.

Its product of digits (8064) is a multiple of the sum of its prime divisors (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7821197) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 411633 + ... + 411651.

Almost surely, 2^7821198 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7821198, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11618880).

7821198 is an abundant number, since it is smaller than the sum of its proper divisors (15416562).

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

7821198 is a wasteful number, since it uses less digits than its factorization.

7821198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65 (or 42 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 7821198 is about 2796.6404845815. The cubic root of 7821198 is about 198.4987426611.

The spelling of 7821198 in words is "seven million, eight hundred twenty-one thousand, one hundred ninety-eight".