21210102 has 24 divisors (see below), whose sum is σ = 47198736. Its totient is φ = 6878736.

The previous prime is 21210097. The next prime is 21210103. The reversal of 21210102 is 20101212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15258 + ... + 16589.

It is an arithmetic number, because the mean of its divisors is an integer number (1966614).

Almost surely, 2^21210102 is an apocalyptic number.

21210102 is an abundant number, since it is smaller than the sum of its proper divisors (25988634).

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

21210102 is a wasteful number, since it uses less digits than its factorization.

21210102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31892 (or 31889 counting only the distinct ones).

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

The square root of 21210102 is about 4605.4426497352. The cubic root of 21210102 is about 276.8094542056.

Adding to 21210102 its reverse (20101212), we get a palindrome (41311314).

It can be divided in two parts, 21210 and 102, that added together give a palindrome (21312).

The spelling of 21210102 in words is "twenty-one million, two hundred ten thousand, one hundred two".