21220110 has 32 divisors (see below), whose sum is σ = 56587680. Its totient is φ = 5658624.

The previous prime is 21220109. The next prime is 21220153. The reversal of 21220110 is 1102212.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21220092 and 21220101.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39027 + ... + 39566.

It is an arithmetic number, because the mean of its divisors is an integer number (1768365).

Almost surely, 2^21220110 is an apocalyptic number.

21220110 is an abundant number, since it is smaller than the sum of its proper divisors (35367570).

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

21220110 is a wasteful number, since it uses less digits than its factorization.

21220110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78609 (or 78603 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21220110 is about 4606.5290621030. The cubic root of 21220110 is about 276.8529849315.

Adding to 21220110 its reverse (1102212), we get a palindrome (22322322).

The spelling of 21220110 in words is "twenty-one million, two hundred twenty thousand, one hundred ten".