21135384 has 32 divisors (see below), whose sum is σ = 58710000. Its totient is φ = 7045056.

The previous prime is 21135371. The next prime is 21135419. The reversal of 21135384 is 48353112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48709 + ... + 49140.

Almost surely, 2^21135384 is an apocalyptic number.

21135384 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21135384 is an abundant number, since it is smaller than the sum of its proper divisors (37574616).

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

21135384 is a wasteful number, since it uses less digits than its factorization.

21135384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97864 (or 97854 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 21135384 is about 4597.3235692085. The cubic root of 21135384 is about 276.4840277794.

Adding to 21135384 its reverse (48353112), we get a palindrome (69488496).

The spelling of 21135384 in words is "twenty-one million, one hundred thirty-five thousand, three hundred eighty-four".