21221708 has 24 divisors (see below), whose sum is σ = 39486720. Its totient is φ = 9951120.

The previous prime is 21221693. The next prime is 21221731. The reversal of 21221708 is 80712212.

21221708 = T₃₄₇ + T₃₄₈ + ... + T₅₅₂.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 6473 + ... + 9183.

It is an arithmetic number, because the mean of its divisors is an integer number (1645280).

Almost surely, 2^21221708 is an apocalyptic number.

It is an amenable number.

21221708 is a deficient number, since it is larger than the sum of its proper divisors (18265012).

21221708 is a wasteful number, since it uses less digits than its factorization.

21221708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2837 (or 2835 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 21221708 is about 4606.7025083024. The cubic root of 21221708 is about 276.8599343137.

The spelling of 21221708 in words is "twenty-one million, two hundred twenty-one thousand, seven hundred eight".