21670330 has 16 divisors (see below), whose sum is σ = 42552864. Its totient is φ = 7880080.

The previous prime is 21670321. The next prime is 21670331. The reversal of 21670330 is 3307612.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21670331) 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 7 ways as a sum of consecutive naturals, for example, 98392 + ... + 98611.

It is an arithmetic number, because the mean of its divisors is an integer number (2659554).

Almost surely, 2^21670330 is an apocalyptic number.

21670330 is a deficient number, since it is larger than the sum of its proper divisors (20882534).

21670330 is a wasteful number, since it uses less digits than its factorization.

21670330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197021.

The product of its (nonzero) digits is 756, while the sum is 22.

The square root of 21670330 is about 4655.1401697478. The cubic root of 21670330 is about 278.7972645360.

Adding to 21670330 its reverse (3307612), we get a palindrome (24977942).

The spelling of 21670330 in words is "twenty-one million, six hundred seventy thousand, three hundred thirty".