21706258 has 32 divisors (see below), whose sum is σ = 38404224. Its totient is φ = 9009792.

The previous prime is 21706253. The next prime is 21706259. The reversal of 21706258 is 85260712.

It is not an unprimeable number, because it can be changed into a prime (21706253) 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, 68316 + ... + 68632.

It is an arithmetic number, because the mean of its divisors is an integer number (1200132).

Almost surely, 2^21706258 is an apocalyptic number.

21706258 is a deficient number, since it is larger than the sum of its proper divisors (16697966).

21706258 is a wasteful number, since it uses less digits than its factorization.

21706258 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 21706258 is about 4658.9975316585. The cubic root of 21706258 is about 278.9512553854.

The spelling of 21706258 in words is "twenty-one million, seven hundred six thousand, two hundred fifty-eight".