21908770 has 32 divisors (see below), whose sum is σ = 42835968. Its totient is φ = 8019648.

The previous prime is 21908753. The next prime is 21908771. The reversal of 21908770 is 7780912.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21908771) 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, 15847 + ... + 17173.

It is an arithmetic number, because the mean of its divisors is an integer number (1338624).

Almost surely, 2^21908770 is an apocalyptic number.

21908770 is a deficient number, since it is larger than the sum of its proper divisors (20927198).

21908770 is a wasteful number, since it uses less digits than its factorization.

21908770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1474.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 21908770 is about 4680.6805060803. The cubic root of 21908770 is about 279.8160781945.

The spelling of 21908770 in words is "twenty-one million, nine hundred eight thousand, seven hundred seventy".