21420102 has 48 divisors (see below), whose sum is σ = 49689792. Its totient is φ = 6103680.

The previous prime is 21420097. The next prime is 21420103. The reversal of 21420102 is 20102412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420103) 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 23 ways as a sum of consecutive naturals, for example, 18513 + ... + 19635.

It is an arithmetic number, because the mean of its divisors is an integer number (1035204).

Almost surely, 2^21420102 is an apocalyptic number.

21420102 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21420102, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24844896).

21420102 is an abundant number, since it is smaller than the sum of its proper divisors (28269690).

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

21420102 is a wasteful number, since it uses less digits than its factorization.

21420102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1173 (or 1156 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21420102 is about 4628.1856056126. The cubic root of 21420102 is about 277.7200138140.

Adding to 21420102 its reverse (20102412), we get a palindrome (41522514).

The spelling of 21420102 in words is "twenty-one million, four hundred twenty thousand, one hundred two".