21166601 has 8 divisors (see below), whose sum is σ = 22292160. Its totient is φ = 20058192.

The previous prime is 21166597. The next prime is 21166609. The reversal of 21166601 is 10666112.

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

It is a cyclic number.

It is not a de Polignac number, because 21166601 - 2² = 21166597 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21166609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1715 + ... + 6728.

It is an arithmetic number, because the mean of its divisors is an integer number (2786520).

Almost surely, 2^21166601 is an apocalyptic number.

It is an amenable number.

21166601 is a deficient number, since it is larger than the sum of its proper divisors (1125559).

21166601 is a wasteful number, since it uses less digits than its factorization.

21166601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8575.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21166601 is about 4600.7174440515. The cubic root of 21166601 is about 276.6200832846.

The spelling of 21166601 in words is "twenty-one million, one hundred sixty-six thousand, six hundred one".