21676945 has 8 divisors (see below), whose sum is σ = 26617536. Its totient is φ = 16938096.

The previous prime is 21676943. The next prime is 21676957. The reversal of 21676945 is 54967612.

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 21676945 - 2¹ = 21676943 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21676898 and 21676907.

It is not an unprimeable number, because it can be changed into a prime (21676943) 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, 50197 + ... + 50626.

It is an arithmetic number, because the mean of its divisors is an integer number (3327192).

Almost surely, 2^21676945 is an apocalyptic number.

It is an amenable number.

21676945 is a deficient number, since it is larger than the sum of its proper divisors (4940591).

21676945 is a wasteful number, since it uses less digits than its factorization.

21676945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100871.

The product of its digits is 90720, while the sum is 40.

The square root of 21676945 is about 4655.8506204559. The cubic root of 21676945 is about 278.8256298367.

The spelling of 21676945 in words is "twenty-one million, six hundred seventy-six thousand, nine hundred forty-five".