21630347 has 8 divisors (see below), whose sum is σ = 22155216. Its totient is φ = 21111552.

The previous prime is 21630337. The next prime is 21630353. The reversal of 21630347 is 74303612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21630347 is a prime.

It is a super-2 number, since 2×21630347² = 935743822680818, which contains 22 as substring.

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 (21630337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6143 + ... + 8999.

It is an arithmetic number, because the mean of its divisors is an integer number (2769402).

Almost surely, 2^21630347 is an apocalyptic number.

21630347 is a deficient number, since it is larger than the sum of its proper divisors (524869).

21630347 is a wasteful number, since it uses less digits than its factorization.

21630347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3037.

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 21630347 is about 4650.8436869024. The cubic root of 21630347 is about 278.6256933328.

Adding to 21630347 its reverse (74303612), we get a palindrome (95933959).

The spelling of 21630347 in words is "twenty-one million, six hundred thirty thousand, three hundred forty-seven".