21764706 has 8 divisors (see below), whose sum is σ = 43529424. Its totient is φ = 7254900.

The previous prime is 21764669. The next prime is 21764711. The reversal of 21764706 is 60746712.

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

21764706 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1813720 + ... + 1813731.

It is an arithmetic number, because the mean of its divisors is an integer number (5441178).

Almost surely, 2^21764706 is an apocalyptic number.

21764706 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.

21764706 is a wasteful number, since it uses less digits than its factorization.

21764706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3627456.

The product of its (nonzero) digits is 14112, while the sum is 33.

The square root of 21764706 is about 4665.2659088202. The cubic root of 21764706 is about 279.2014064537.

The spelling of 21764706 in words is "twenty-one million, seven hundred sixty-four thousand, seven hundred six".