21076643 has 16 divisors (see below), whose sum is σ = 26046720. Its totient is φ = 16648416.

The previous prime is 21076639. The next prime is 21076667. The reversal of 21076643 is 34667012.

It is a cyclic number.

It is not a de Polignac number, because 21076643 - 2² = 21076639 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21076603) 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 15 ways as a sum of consecutive naturals, for example, 2780 + ... + 7062.

It is an arithmetic number, because the mean of its divisors is an integer number (1627920).

Almost surely, 2^21076643 is an apocalyptic number.

21076643 is a deficient number, since it is larger than the sum of its proper divisors (4970077).

21076643 is a wasteful number, since it uses less digits than its factorization.

21076643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4346.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 21076643 is about 4590.9305157016. The cubic root of 21076643 is about 276.2276485946.

The spelling of 21076643 in words is "twenty-one million, seventy-six thousand, six hundred forty-three".