21680870 has 16 divisors (see below), whose sum is σ = 39104208. Its totient is φ = 8654880.

The previous prime is 21680861. The next prime is 21680887. The reversal of 21680870 is 7808612.

It is a congruent number.

It is an unprimeable number.

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, 3812 + ... + 7608.

It is an arithmetic number, because the mean of its divisors is an integer number (2444013).

Almost surely, 2^21680870 is an apocalyptic number.

21680870 is a deficient number, since it is larger than the sum of its proper divisors (17423338).

21680870 is a wasteful number, since it uses less digits than its factorization.

21680870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4375.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 21680870 is about 4656.2721140414. The cubic root of 21680870 is about 278.8424576162.

The spelling of 21680870 in words is "twenty-one million, six hundred eighty thousand, eight hundred seventy".