21220670 has 16 divisors (see below), whose sum is σ = 38918880. Its totient is φ = 8327904.

The previous prime is 21220649. The next prime is 21220687. The reversal of 21220670 is 7602212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19490 + ... + 20549.

It is an arithmetic number, because the mean of its divisors is an integer number (2432430).

Almost surely, 2^21220670 is an apocalyptic number.

21220670 is a deficient number, since it is larger than the sum of its proper divisors (17698210).

21220670 is a wasteful number, since it uses less digits than its factorization.

21220670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40099.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21220670 is about 4606.5898449938. The cubic root of 21220670 is about 276.8554202991.

Adding to 21220670 its reverse (7602212), we get a palindrome (28822882).

The spelling of 21220670 in words is "twenty-one million, two hundred twenty thousand, six hundred seventy".