21694201 has 2 divisors, whose sum is σ = 21694202. Its totient is φ = 21694200.

The previous prime is 21694151. The next prime is 21694217. The reversal of 21694201 is 10249612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20793600 + 900601 = 4560^2 + 949^2 .

It is a cyclic number.

It is not a de Polignac number, because 21694201 - 2¹⁵ = 21661433 is a prime.

It is equal to p_1371085 and since 21694201 and 1371085 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21694271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10847100 + 10847101.

It is an arithmetic number, because the mean of its divisors is an integer number (10847101).

Almost surely, 2^21694201 is an apocalyptic number.

It is an amenable number.

21694201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21694201 is an equidigital number, since it uses as much as digits as its factorization.

21694201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21694201 is about 4657.7034040394. The cubic root of 21694201 is about 278.8995968851.

The spelling of 21694201 in words is "twenty-one million, six hundred ninety-four thousand, two hundred one".