21154406 has 24 divisors (see below), whose sum is σ = 39273264. Its totient is φ = 8367840.

The previous prime is 21154403. The next prime is 21154447. The reversal of 21154406 is 60445112.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2105 + ... + 6836.

It is an arithmetic number, because the mean of its divisors is an integer number (1636386).

Almost surely, 2^21154406 is an apocalyptic number.

21154406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21154406 is a deficient number, since it is larger than the sum of its proper divisors (18118858).

21154406 is a wasteful number, since it uses less digits than its factorization.

21154406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8976 (or 8963 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21154406 is about 4599.3919163298. The cubic root of 21154406 is about 276.5669487894.

Adding to 21154406 its reverse (60445112), we get a palindrome (81599518).

The spelling of 21154406 in words is "twenty-one million, one hundred fifty-four thousand, four hundred six".