21660654 has 8 divisors (see below), whose sum is σ = 43321320. Its totient is φ = 7220216.

The previous prime is 21660643. The next prime is 21660677. The reversal of 21660654 is 45606612.

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

21660654 is an admirable number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 1805049 + ... + 1805060.

It is an arithmetic number, because the mean of its divisors is an integer number (5415165).

Almost surely, 2^21660654 is an apocalyptic number.

21660654 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.

21660654 is a wasteful number, since it uses less digits than its factorization.

21660654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3610114.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 21660654 is about 4654.1007724371. The cubic root of 21660654 is about 278.7557631846.

It can be divided in two parts, 21 and 660654, that added together give a triangular number (660675 = T₁₁₄₉).

The spelling of 21660654 in words is "twenty-one million, six hundred sixty thousand, six hundred fifty-four".