7131821 has 4 divisors (see below), whose sum is σ = 7507200. Its totient is φ = 6756444.

The previous prime is 7131797. The next prime is 7131841. The reversal of 7131821 is 1281317.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 7131821 - 2¹⁰ = 7130797 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7131841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 187661 + ... + 187698.

It is an arithmetic number, because the mean of its divisors is an integer number (1876800).

Almost surely, 2^7131821 is an apocalyptic number.

It is an amenable number.

7131821 is a deficient number, since it is larger than the sum of its proper divisors (375379).

7131821 is a wasteful number, since it uses less digits than its factorization.

7131821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375378.

The product of its digits is 336, while the sum is 23.

The square root of 7131821 is about 2670.5469477244. The cubic root of 7131821 is about 192.4864419529.

The spelling of 7131821 in words is "seven million, one hundred thirty-one thousand, eight hundred twenty-one".