21071706 has 8 divisors (see below), whose sum is σ = 42143424. Its totient is φ = 7023900.

The previous prime is 21071683. The next prime is 21071707. The reversal of 21071706 is 60717012.

It is a sphenic number, since it is the product of 3 distinct primes.

21071706 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21071707) 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 3 ways as a sum of consecutive naturals, for example, 1755970 + ... + 1755981.

It is an arithmetic number, because the mean of its divisors is an integer number (5267928).

Almost surely, 2^21071706 is an apocalyptic number.

21071706 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21071706 is a wasteful number, since it uses less digits than its factorization.

21071706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3511956.

The product of its (nonzero) digits is 588, while the sum is 24.

The square root of 21071706 is about 4590.3927936507. The cubic root of 21071706 is about 276.2060790244.

Adding to 21071706 its reverse (60717012), we get a palindrome (81788718).

It can be divided in two parts, 2 and 1071706, that multiplied together give a palindrome (2143412).

The spelling of 21071706 in words is "twenty-one million, seventy-one thousand, seven hundred six".