21306735 has 36 divisors (see below), whose sum is σ = 38317032. Its totient is φ = 10952256.

The previous prime is 21306713. The next prime is 21306739. The reversal of 21306735 is 53760312.

It is a happy number.

It is not a de Polignac number, because 21306735 - 2⁸ = 21306479 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21306699 and 21306708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21306739) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 37564 + ... + 38126.

It is an arithmetic number, because the mean of its divisors is an integer number (1064362).

Almost surely, 2^21306735 is an apocalyptic number.

21306735 is a deficient number, since it is larger than the sum of its proper divisors (17010297).

21306735 is a wasteful number, since it uses less digits than its factorization.

21306735 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632 (or 600 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 27.

The square root of 21306735 is about 4615.9219014190. The cubic root of 21306735 is about 277.2291977141.

The spelling of 21306735 in words is "twenty-one million, three hundred six thousand, seven hundred thirty-five".