21842128 has 40 divisors (see below), whose sum is σ = 52764480. Its totient is φ = 8509440.

The previous prime is 21842123. The next prime is 21842131. The reversal of 21842128 is 82124812.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21842096 and 21842105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21842123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7633 + ... + 10096.

It is an arithmetic number, because the mean of its divisors is an integer number (1319112).

Almost surely, 2^21842128 is an apocalyptic number.

21842128 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21842128 is an abundant number, since it is smaller than the sum of its proper divisors (30922352).

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

21842128 is a wasteful number, since it uses less digits than its factorization.

21842128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17755 (or 17749 counting only the distinct ones).

The product of its digits is 2048, while the sum is 28.

The square root of 21842128 is about 4673.5562476555. The cubic root of 21842128 is about 279.5320756026.

The spelling of 21842128 in words is "twenty-one million, eight hundred forty-two thousand, one hundred twenty-eight".