21508102 has 16 divisors (see below), whose sum is σ = 40223232. Its totient is φ = 8379720.

The previous prime is 21508099. The next prime is 21508117. The reversal of 21508102 is 20180512.

It is a self number, because there is not a number n which added to its sum of digits gives 21508102.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69678 + ... + 69985.

It is an arithmetic number, because the mean of its divisors is an integer number (2513952).

Almost surely, 2^21508102 is an apocalyptic number.

21508102 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21508102 is a deficient number, since it is larger than the sum of its proper divisors (18715130).

21508102 is a wasteful number, since it uses less digits than its factorization.

21508102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139683.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 21508102 is about 4637.6828265848. The cubic root of 21508102 is about 278.0998123384.

Adding to 21508102 its reverse (20180512), we get a palindrome (41688614).

The spelling of 21508102 in words is "twenty-one million, five hundred eight thousand, one hundred two".