20916667 has 4 divisors (see below), whose sum is σ = 20945056. Its totient is φ = 20888280.

The previous prime is 20916589. The next prime is 20916673. The reversal of 20916667 is 76661902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76661902 = 2 ⋅38330951.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20916667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20916697) 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, 13059 + ... + 14572.

It is an arithmetic number, because the mean of its divisors is an integer number (5236264).

Almost surely, 2^20916667 is an apocalyptic number.

20916667 is a deficient number, since it is larger than the sum of its proper divisors (28389).

20916667 is an equidigital number, since it uses as much as digits as its factorization.

20916667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28388.

The product of its (nonzero) digits is 27216, while the sum is 37.

The square root of 20916667 is about 4573.4742811128. The cubic root of 20916667 is about 275.5269982534.

The spelling of 20916667 in words is "twenty million, nine hundred sixteen thousand, six hundred sixty-seven".