21680270 has 32 divisors (see below), whose sum is σ = 41910048. Its totient is φ = 8045568.

The previous prime is 21680257. The next prime is 21680279. The reversal of 21680270 is 7208612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680279) 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 15 ways as a sum of consecutive naturals, for example, 11537 + ... + 13283.

It is an arithmetic number, because the mean of its divisors is an integer number (1309689).

Almost surely, 2^21680270 is an apocalyptic number.

21680270 is a deficient number, since it is larger than the sum of its proper divisors (20229778).

21680270 is a wasteful number, since it uses less digits than its factorization.

21680270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1844.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21680270 is about 4656.2076843715. The cubic root of 21680270 is about 278.8398853483.

Adding to 21680270 its reverse (7208612), we get a palindrome (28888882).

The spelling of 21680270 in words is "twenty-one million, six hundred eighty thousand, two hundred seventy".