21630707 has 6 divisors (see below), whose sum is σ = 25162308. Its totient is φ = 18540564.

The previous prime is 21630689. The next prime is 21630727. The reversal of 21630707 is 70703612.

It is not a de Polignac number, because 21630707 - 2⁸ = 21630451 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21630727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 220673 + ... + 220770.

It is an arithmetic number, because the mean of its divisors is an integer number (4193718).

Almost surely, 2^21630707 is an apocalyptic number.

21630707 is a deficient number, since it is larger than the sum of its proper divisors (3531601).

21630707 is an equidigital number, since it uses as much as digits as its factorization.

21630707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441457 (or 441450 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 26.

The square root of 21630707 is about 4650.8823893967. The cubic root of 21630707 is about 278.6272390730.

The spelling of 21630707 in words is "twenty-one million, six hundred thirty thousand, seven hundred seven".