21102940 has 48 divisors (see below), whose sum is σ = 46335744. Its totient is φ = 8064000.

The previous prime is 21102931. The next prime is 21102941. The reversal of 21102940 is 4920112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62452 + ... + 62788.

It is an arithmetic number, because the mean of its divisors is an integer number (965328).

Almost surely, 2^21102940 is an apocalyptic number.

21102940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21102940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23167872).

21102940 is an abundant number, since it is smaller than the sum of its proper divisors (25232804).

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

21102940 is a wasteful number, since it uses less digits than its factorization.

21102940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478 (or 476 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 21102940 is about 4593.7936392485. The cubic root of 21102940 is about 276.3424824975.

It can be divided in two parts, 2110 and 2940, that added together give a triangular number (5050 = T₁₀₀).

The spelling of 21102940 in words is "twenty-one million, one hundred two thousand, nine hundred forty".