21706106 has 4 divisors (see below), whose sum is σ = 32559162. Its totient is φ = 10853052.

The previous prime is 21706103. The next prime is 21706109. The reversal of 21706106 is 60160712.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21706103) and next prime (21706109).

It can be written as a sum of positive squares in only one way, i.e., 17147881 + 4558225 = 4141^2 + 2135^2 .

It is not an unprimeable number, because it can be changed into a prime (21706103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5426525 + ... + 5426528.

Almost surely, 2^21706106 is an apocalyptic number.

21706106 is a deficient number, since it is larger than the sum of its proper divisors (10853056).

21706106 is a wasteful number, since it uses less digits than its factorization.

21706106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10853055.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 21706106 is about 4658.9812191079. The cubic root of 21706106 is about 278.9506042569.

Adding to 21706106 its reverse (60160712), we get a palindrome (81866818).

It can be divided in two parts, 21706 and 106, that added together give a palindrome (21812).

The spelling of 21706106 in words is "twenty-one million, seven hundred six thousand, one hundred six".