21376643 has 8 divisors (see below), whose sum is σ = 21752640. Its totient is φ = 21003840.

The previous prime is 21376627. The next prime is 21376651. The reversal of 21376643 is 34667312.

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 21376643 - 2⁴ = 21376627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21376603) 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, 15446 + ... + 16772.

It is an arithmetic number, because the mean of its divisors is an integer number (2719080).

Almost surely, 2^21376643 is an apocalyptic number.

21376643 is a deficient number, since it is larger than the sum of its proper divisors (375997).

21376643 is a wasteful number, since it uses less digits than its factorization.

21376643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1597.

The product of its digits is 18144, while the sum is 32.

The square root of 21376643 is about 4623.4881853423. The cubic root of 21376643 is about 277.5320656613.

The spelling of 21376643 in words is "twenty-one million, three hundred seventy-six thousand, six hundred forty-three".