21066654 has 32 divisors (see below), whose sum is σ = 48658176. Its totient is φ = 5955840.

The previous prime is 21066641. The next prime is 21066677. The reversal of 21066654 is 45666012.

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 15 ways as a sum of consecutive naturals, for example, 1489 + ... + 6659.

It is an arithmetic number, because the mean of its divisors is an integer number (1520568).

Almost surely, 2^21066654 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21066654, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24329088).

21066654 is an abundant number, since it is smaller than the sum of its proper divisors (27591522).

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

21066654 is a wasteful number, since it uses less digits than its factorization.

21066654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5280.

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

The square root of 21066654 is about 4589.8424809573. The cubic root of 21066654 is about 276.1840035353.

The spelling of 21066654 in words is "twenty-one million, sixty-six thousand, six hundred fifty-four".