21002108 has 6 divisors (see below), whose sum is σ = 36753696. Its totient is φ = 10501052.

The previous prime is 21002101. The next prime is 21002129. The reversal of 21002108 is 80120012.

It is a junction number, because it is equal to n+sod(n) for n = 21002092 and 21002101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002101) 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 as a sum of consecutive naturals, namely, 2625260 + ... + 2625267.

It is an arithmetic number, because the mean of its divisors is an integer number (6125616).

Almost surely, 2^21002108 is an apocalyptic number.

It is an amenable number.

21002108 is a deficient number, since it is larger than the sum of its proper divisors (15751588).

21002108 is a wasteful number, since it uses less digits than its factorization.

21002108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5250531 (or 5250529 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 21002108 is about 4582.8056908405. The cubic root of 21002108 is about 275.9016487771.

It can be divided in two parts, 2100 and 2108, that multiplied together give a triangular number (4426800 = T₂₉₇₅).

The spelling of 21002108 in words is "twenty-one million, two thousand, one hundred eight".