21680767 has 4 divisors (see below), whose sum is σ = 22821880. Its totient is φ = 20539656.

The previous prime is 21680741. The next prime is 21680783. The reversal of 21680767 is 76708612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21680767 - 2⁷ = 21680639 is a prime.

It is a super-3 number, since 3×21680767³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680707) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 570528 + ... + 570565.

It is an arithmetic number, because the mean of its divisors is an integer number (5705470).

Almost surely, 2^21680767 is an apocalyptic number.

21680767 is a deficient number, since it is larger than the sum of its proper divisors (1141113).

21680767 is a wasteful number, since it uses less digits than its factorization.

21680767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1141112.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 21680767 is about 4656.2610536782. The cubic root of 21680767 is about 278.8420160469.

The spelling of 21680767 in words is "twenty-one million, six hundred eighty thousand, seven hundred sixty-seven".