21716767 has 2 divisors, whose sum is σ = 21716768. Its totient is φ = 21716766.

The previous prime is 21716749. The next prime is 21716809. The reversal of 21716767 is 76761712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21716767 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21716567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10858383 + 10858384.

It is an arithmetic number, because the mean of its divisors is an integer number (10858384).

Almost surely, 2^21716767 is an apocalyptic number.

21716767 is a deficient number, since it is larger than the sum of its proper divisors (1).

21716767 is an equidigital number, since it uses as much as digits as its factorization.

21716767 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24696, while the sum is 37.

The square root of 21716767 is about 4660.1252129101. The cubic root of 21716767 is about 278.9962658425.

The spelling of 21716767 in words is "twenty-one million, seven hundred sixteen thousand, seven hundred sixty-seven".