21766001 has 16 divisors (see below), whose sum is σ = 24595200. Its totient is φ = 19139328.

The previous prime is 21765983. The next prime is 21766007. The reversal of 21766001 is 10066712.

It is a cyclic number.

It is not a de Polignac number, because 21766001 - 2¹⁴ = 21749617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21766007) by changing a digit.

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, 25091 + ... + 25943.

It is an arithmetic number, because the mean of its divisors is an integer number (1537200).

Almost surely, 2^21766001 is an apocalyptic number.

It is an amenable number.

21766001 is a deficient number, since it is larger than the sum of its proper divisors (2829199).

21766001 is a wasteful number, since it uses less digits than its factorization.

21766001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968.

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

The square root of 21766001 is about 4665.4046984158. The cubic root of 21766001 is about 279.2069438384.

The spelling of 21766001 in words is "twenty-one million, seven hundred sixty-six thousand, one".