21680246 has 12 divisors (see below), whose sum is σ = 37829988. Its totient is φ = 9291492.

The previous prime is 21680231. The next prime is 21680249. The reversal of 21680246 is 64208612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680249) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 110516 + ... + 110711.

It is an arithmetic number, because the mean of its divisors is an integer number (3152499).

Almost surely, 2^21680246 is an apocalyptic number.

21680246 is a deficient number, since it is larger than the sum of its proper divisors (16149742).

21680246 is a wasteful number, since it uses less digits than its factorization.

21680246 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221243 (or 221236 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21680246 is about 4656.2051071661. The cubic root of 21680246 is about 278.8397824566.

Adding to 21680246 its reverse (64208612), we get a palindrome (85888858).

The spelling of 21680246 in words is "twenty-one million, six hundred eighty thousand, two hundred forty-six".