21630959 has 8 divisors (see below), whose sum is σ = 24760320. Its totient is φ = 18511416.

The previous prime is 21630923. The next prime is 21630991. The reversal of 21630959 is 95903612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21630959 - 2²⁰ = 20582383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21630359) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3122 + ... + 7280.

It is an arithmetic number, because the mean of its divisors is an integer number (3095040).

Almost surely, 2^21630959 is an apocalyptic number.

21630959 is a deficient number, since it is larger than the sum of its proper divisors (3129361).

21630959 is an equidigital number, since it uses as much as digits as its factorization.

21630959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4909.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 21630959 is about 4650.9094809510. The cubic root of 21630959 is about 278.6283210810.

The spelling of 21630959 in words is "twenty-one million, six hundred thirty thousand, nine hundred fifty-nine".