21386040 has 64 divisors (see below), whose sum is σ = 69098400. Its totient is φ = 5263872.

The previous prime is 21385999. The next prime is 21386047. The reversal of 21386040 is 4068312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21386040.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21386047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5295 + ... + 8414.

Almost surely, 2^21386040 is an apocalyptic number.

21386040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21386040 is an abundant number, since it is smaller than the sum of its proper divisors (47712360).

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

21386040 is a wasteful number, since it uses less digits than its factorization.

21386040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13736 (or 13732 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21386040 is about 4624.5042977599. The cubic root of 21386040 is about 277.5727266570.

The spelling of 21386040 in words is "twenty-one million, three hundred eighty-six thousand, forty".