21929716 has 6 divisors (see below), whose sum is σ = 38377010. Its totient is φ = 10964856.

The previous prime is 21929707. The next prime is 21929717. The reversal of 21929716 is 61792912.

It can be written as a sum of positive squares in only one way, i.e., 19980900 + 1948816 = 4470^2 + 1396^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2741211 + ... + 2741218.

Almost surely, 2^21929716 is an apocalyptic number.

It is an amenable number.

21929716 is a deficient number, since it is larger than the sum of its proper divisors (16447294).

21929716 is a wasteful number, since it uses less digits than its factorization.

21929716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5482433 (or 5482431 counting only the distinct ones).

The product of its digits is 13608, while the sum is 37.

The square root of 21929716 is about 4682.9174667081. The cubic root of 21929716 is about 279.9052230247.

The spelling of 21929716 in words is "twenty-one million, nine hundred twenty-nine thousand, seven hundred sixteen".