21084797 has 2 divisors, whose sum is σ = 21084798. Its totient is φ = 21084796.

The previous prime is 21084787. The next prime is 21084803. The reversal of 21084797 is 79748012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14638276 + 6446521 = 3826^2 + 2539^2 .

It is a cyclic number.

It is not a de Polignac number, because 21084797 - 2⁶ = 21084733 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21084797.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21084727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10542398 + 10542399.

It is an arithmetic number, because the mean of its divisors is an integer number (10542399).

Almost surely, 2^21084797 is an apocalyptic number.

It is an amenable number.

21084797 is a deficient number, since it is larger than the sum of its proper divisors (1).

21084797 is an equidigital number, since it uses as much as digits as its factorization.

21084797 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 21084797 is about 4591.8184850885. The cubic root of 21084797 is about 276.2632657443.

The spelling of 21084797 in words is "twenty-one million, eighty-four thousand, seven hundred ninety-seven".