21906201 has 8 divisors (see below), whose sum is σ = 29255104. Its totient is φ = 14580720.

The previous prime is 21906179. The next prime is 21906233. The reversal of 21906201 is 10260912.

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

It is not a de Polignac number, because 21906201 - 2¹⁵ = 21873433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21906301) 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, 3541 + ... + 7506.

It is an arithmetic number, because the mean of its divisors is an integer number (3656888).

Almost surely, 2^21906201 is an apocalyptic number.

It is an amenable number.

21906201 is a deficient number, since it is larger than the sum of its proper divisors (7348903).

21906201 is a wasteful number, since it uses less digits than its factorization.

21906201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11711.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 21906201 is about 4680.4060721266. The cubic root of 21906201 is about 279.8051407845.

The spelling of 21906201 in words is "twenty-one million, nine hundred six thousand, two hundred one".