21906772 has 12 divisors (see below), whose sum is σ = 40354720. Its totient is φ = 10376856.

The previous prime is 21906767. The next prime is 21906809. The reversal of 21906772 is 27760912.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 144048 + ... + 144199.

Almost surely, 2^21906772 is an apocalyptic number.

It is an amenable number.

21906772 is a deficient number, since it is larger than the sum of its proper divisors (18447948).

21906772 is a wasteful number, since it uses less digits than its factorization.

21906772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288270 (or 288268 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 34.

The square root of 21906772 is about 4680.4670707099. The cubic root of 21906772 is about 279.8075718670.

The spelling of 21906772 in words is "twenty-one million, nine hundred six thousand, seven hundred seventy-two".