21381736 has 16 divisors (see below), whose sum is σ = 40140000. Its totient is φ = 10677744.

The previous prime is 21381653. The next prime is 21381739. The reversal of 21381736 is 63718312.

It is a junction number, because it is equal to n+sod(n) for n = 21381698 and 21381707.

It is not an unprimeable number, because it can be changed into a prime (21381739) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11101 + ... + 12883.

It is an arithmetic number, because the mean of its divisors is an integer number (2508750).

Almost surely, 2^21381736 is an apocalyptic number.

It is an amenable number.

21381736 is a deficient number, since it is larger than the sum of its proper divisors (18758264).

21381736 is a wasteful number, since it uses less digits than its factorization.

21381736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3288 (or 3284 counting only the distinct ones).

The product of its digits is 6048, while the sum is 31.

The square root of 21381736 is about 4624.0389271718. The cubic root of 21381736 is about 277.5541046467.

The spelling of 21381736 in words is "twenty-one million, three hundred eighty-one thousand, seven hundred thirty-six".