21673766 has 4 divisors (see below), whose sum is σ = 32510652. Its totient is φ = 10836882.

The previous prime is 21673753. The next prime is 21673787. The reversal of 21673766 is 66737612.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5418440 + ... + 5418443.

It is an arithmetic number, because the mean of its divisors is an integer number (8127663).

Almost surely, 2^21673766 is an apocalyptic number.

21673766 is a deficient number, since it is larger than the sum of its proper divisors (10836886).

21673766 is a wasteful number, since it uses less digits than its factorization.

21673766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10836885.

The product of its digits is 63504, while the sum is 38.

The square root of 21673766 is about 4655.5092095280. The cubic root of 21673766 is about 278.8119989182.

The spelling of 21673766 in words is "twenty-one million, six hundred seventy-three thousand, seven hundred sixty-six".