21198661 has 8 divisors (see below), whose sum is σ = 24343200. Its totient is φ = 18257040.

The previous prime is 21198631. The next prime is 21198673. The reversal of 21198661 is 16689112.

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 21198661 - 2¹³ = 21190469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21198631) 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, 50506 + ... + 50923.

It is an arithmetic number, because the mean of its divisors is an integer number (3042900).

Almost surely, 2^21198661 is an apocalyptic number.

It is an amenable number.

21198661 is a deficient number, since it is larger than the sum of its proper divisors (3144539).

21198661 is a wasteful number, since it uses less digits than its factorization.

21198661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101459.

The product of its digits is 5184, while the sum is 34.

The square root of 21198661 is about 4604.2003648842. The cubic root of 21198661 is about 276.7596737351.

The spelling of 21198661 in words is "twenty-one million, one hundred ninety-eight thousand, six hundred sixty-one".