21421110 has 16 divisors (see below), whose sum is σ = 51410736. Its totient is φ = 5712288.

The previous prime is 21421097. The next prime is 21421117. The reversal of 21421110 is 1112412.

It is a happy 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 (21421117) 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 7 ways as a sum of consecutive naturals, for example, 356989 + ... + 357048.

It is an arithmetic number, because the mean of its divisors is an integer number (3213171).

Almost surely, 2^21421110 is an apocalyptic number.

21421110 is an abundant number, since it is smaller than the sum of its proper divisors (29989626).

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

21421110 is a wasteful number, since it uses less digits than its factorization.

21421110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 714047.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 21421110 is about 4628.2945022978. The cubic root of 21421110 is about 277.7243701173.

Adding to 21421110 its reverse (1112412), we get a palindrome (22533522).

The spelling of 21421110 in words is "twenty-one million, four hundred twenty-one thousand, one hundred ten".