21621193 has 8 divisors (see below), whose sum is σ = 23677056. Its totient is φ = 19580400.

The previous prime is 21621181. The next prime is 21621233. The reversal of 21621193 is 39112612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21621193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621113) 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, 646 + ... + 6607.

It is an arithmetic number, because the mean of its divisors is an integer number (2959632).

Almost surely, 2^21621193 is an apocalyptic number.

It is an amenable number.

21621193 is a deficient number, since it is larger than the sum of its proper divisors (2055863).

21621193 is a wasteful number, since it uses less digits than its factorization.

21621193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7535.

The product of its digits is 648, while the sum is 25.

The square root of 21621193 is about 4649.8594602418. The cubic root of 21621193 is about 278.5863828295.

The spelling of 21621193 in words is "twenty-one million, six hundred twenty-one thousand, one hundred ninety-three".