21705654 has 8 divisors (see below), whose sum is σ = 43411320. Its totient is φ = 7235216.

The previous prime is 21705647. The next prime is 21705661. The reversal of 21705654 is 45650712.

It is an interprime number because it is at equal distance from previous prime (21705647) and next prime (21705661).

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

21705654 is an admirable number.

It is a super-2 number, since 2×21705654² = 942270831135432, which contains 22 as substring.

It is a congruent 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, 1808799 + ... + 1808810.

It is an arithmetic number, because the mean of its divisors is an integer number (5426415).

Almost surely, 2^21705654 is an apocalyptic number.

21705654 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.

21705654 is a wasteful number, since it uses less digits than its factorization.

21705654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3617614.

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 21705654 is about 4658.9327103962. The cubic root of 21705654 is about 278.9486679884.

The spelling of 21705654 in words is "twenty-one million, seven hundred five thousand, six hundred fifty-four".