21630319 has 4 divisors (see below), whose sum is σ = 21642280. Its totient is φ = 21618360.

The previous prime is 21630289. The next prime is 21630337. The reversal of 21630319 is 91303612.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21630319 - 2¹⁵ = 21597551 is a prime.

It is a super-2 number, since 2×21630319² = 935741400083522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21630293 and 21630302.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2649 + ... + 7090.

It is an arithmetic number, because the mean of its divisors is an integer number (5410570).

Almost surely, 2^21630319 is an apocalyptic number.

21630319 is a deficient number, since it is larger than the sum of its proper divisors (11961).

21630319 is an equidigital number, since it uses as much as digits as its factorization.

21630319 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11960.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 21630319 is about 4650.8406766949. The cubic root of 21630319 is about 278.6255731078.

The spelling of 21630319 in words is "twenty-one million, six hundred thirty thousand, three hundred nineteen".