1821167406 has 24 divisors (see below), whose sum is σ = 3950771760. Its totient is φ = 606300576.

The previous prime is 1821167357. The next prime is 1821167407. The reversal of 1821167406 is 6047611281.

It is a happy number.

1821167406 is a `hidden beast` number, since 182 + 11 + 67 + 406 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821167407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 47970 + ... + 77093.

It is an arithmetic number, because the mean of its divisors is an integer number (164615490).

Almost surely, 2^1821167406 is an apocalyptic number.

1821167406 is an abundant number, since it is smaller than the sum of its proper divisors (2129604354).

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

1821167406 is a wasteful number, since it uses less digits than its factorization.

1821167406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125880 (or 125877 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 1821167406 is about 42675.1380314112. The cubic root of 1821167406 is about 1221.1901415737.

Adding to 1821167406 its reverse (6047611281), we get a palindrome (7868778687).

The spelling of 1821167406 in words is "one billion, eight hundred twenty-one million, one hundred sixty-seven thousand, four hundred six".