21702851 has 2 divisors, whose sum is σ = 21702852. Its totient is φ = 21702850.

The previous prime is 21702833. The next prime is 21702853. The reversal of 21702851 is 15820712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21702851 is a prime.

Together with 21702853, it forms a pair of twin primes.

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 21702851.

It is not a weakly prime, because it can be changed into another prime (21702853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10851425 + 10851426.

It is an arithmetic number, because the mean of its divisors is an integer number (10851426).

Almost surely, 2^21702851 is an apocalyptic number.

21702851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21702851 is an equidigital number, since it uses as much as digits as its factorization.

21702851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 21702851 is about 4658.6318807135. The cubic root of 21702851 is about 278.9366599532.

The spelling of 21702851 in words is "twenty-one million, seven hundred two thousand, eight hundred fifty-one".