21676664 has 8 divisors (see below), whose sum is σ = 40643760. Its totient is φ = 10838328.

The previous prime is 21676661. The next prime is 21676667. The reversal of 21676664 is 46667612.

It is an interprime number because it is at equal distance from previous prime (21676661) and next prime (21676667).

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21676661) 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 as a sum of consecutive naturals, namely, 1354784 + ... + 1354799.

It is an arithmetic number, because the mean of its divisors is an integer number (5080470).

Almost surely, 2^21676664 is an apocalyptic number.

It is an amenable number.

21676664 is a deficient number, since it is larger than the sum of its proper divisors (18967096).

21676664 is a wasteful number, since it uses less digits than its factorization.

21676664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2709589 (or 2709585 counting only the distinct ones).

The product of its digits is 72576, while the sum is 38.

The square root of 21676664 is about 4655.8204432731. The cubic root of 21676664 is about 278.8244250184.

The spelling of 21676664 in words is "twenty-one million, six hundred seventy-six thousand, six hundred sixty-four".