21161706 has 64 divisors (see below), whose sum is σ = 47606400. Its totient is φ = 6241536.

The previous prime is 21161683. The next prime is 21161717. The reversal of 21161706 is 60716112.

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 31 ways as a sum of consecutive naturals, for example, 122236 + ... + 122408.

It is an arithmetic number, because the mean of its divisors is an integer number (743850).

Almost surely, 2^21161706 is an apocalyptic number.

21161706 is an abundant number, since it is smaller than the sum of its proper divisors (26444694).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21161706 is a wasteful number, since it uses less digits than its factorization.

21161706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21161706 is about 4600.1854310451. The cubic root of 21161706 is about 276.5987578688.

Adding to 21161706 its reverse (60716112), we get a palindrome (81877818).

The spelling of 21161706 in words is "twenty-one million, one hundred sixty-one thousand, seven hundred six".