21191601 has 8 divisors (see below), whose sum is σ = 28478464. Its totient is φ = 14016240.

The previous prime is 21191591. The next prime is 21191603. The reversal of 21191601 is 10619112.

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

It is not a de Polignac number, because 21191601 - 2⁷ = 21191473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21191603) 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 7 ways as a sum of consecutive naturals, for example, 27430 + ... + 28191.

It is an arithmetic number, because the mean of its divisors is an integer number (3559808).

Almost surely, 2^21191601 is an apocalyptic number.

It is an amenable number.

21191601 is a deficient number, since it is larger than the sum of its proper divisors (7286863).

21191601 is a wasteful number, since it uses less digits than its factorization.

21191601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55751.

The product of its (nonzero) digits is 108, while the sum is 21.

The square root of 21191601 is about 4603.4336098178. The cubic root of 21191601 is about 276.7289463187.

The spelling of 21191601 in words is "twenty-one million, one hundred ninety-one thousand, six hundred one".