21171201 has 8 divisors (see below), whose sum is σ = 29455680. Its totient is φ = 13500432.

The previous prime is 21171193. The next prime is 21171203. The reversal of 21171201 is 10217112.

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

It is not a de Polignac number, because 21171201 - 2³ = 21171193 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21171203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 153346 + ... + 153483.

It is an arithmetic number, because the mean of its divisors is an integer number (3681960).

Almost surely, 2^21171201 is an apocalyptic number.

It is an amenable number.

21171201 is a deficient number, since it is larger than the sum of its proper divisors (8284479).

21171201 is a wasteful number, since it uses less digits than its factorization.

21171201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306855.

The product of its (nonzero) digits is 28, while the sum is 15.

The square root of 21171201 is about 4601.2173389224. The cubic root of 21171201 is about 276.6401205155.

Adding to 21171201 its reverse (10217112), we get a palindrome (31388313).

It can be divided in two parts, 21 and 171201, that multiplied together give a triangular number (3595221 = T₂₆₈₁).

The spelling of 21171201 in words is "twenty-one million, one hundred seventy-one thousand, two hundred one".