21630735 has 24 divisors (see below), whose sum is σ = 42850080. Its totient is φ = 9888192.

The previous prime is 21630733. The next prime is 21630761. The reversal of 21630735 is 53703612.

It is a happy number.

21630735 is a `hidden beast` number, since 21 + 630 + 7 + 3 + 5 = 666.

It is not a de Polignac number, because 21630735 - 2¹ = 21630733 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21630699 and 21630708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21630733) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34020 + ... + 34649.

It is an arithmetic number, because the mean of its divisors is an integer number (1785420).

Almost surely, 2^21630735 is an apocalyptic number.

21630735 is a deficient number, since it is larger than the sum of its proper divisors (21219345).

21630735 is a wasteful number, since it uses less digits than its factorization.

21630735 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68687 (or 68684 counting only the distinct ones).

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

The square root of 21630735 is about 4650.8853995772. The cubic root of 21630735 is about 278.6273592966.

The spelling of 21630735 in words is "twenty-one million, six hundred thirty thousand, seven hundred thirty-five".