201678649 has 2 divisors, whose sum is σ = 201678650. Its totient is φ = 201678648.

The previous prime is 201678647. The next prime is 201678679. The reversal of 201678649 is 946876102.

201678649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162741049 + 38937600 = 12757^2 + 6240^2 .

It is a cyclic number.

It is not a de Polignac number, because 201678649 - 2¹ = 201678647 is a prime.

Together with 201678647, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (201678641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100839324 + 100839325.

It is an arithmetic number, because the mean of its divisors is an integer number (100839325).

Almost surely, 2^201678649 is an apocalyptic number.

It is an amenable number.

201678649 is a deficient number, since it is larger than the sum of its proper divisors (1).

201678649 is an equidigital number, since it uses as much as digits as its factorization.

201678649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 201678649 is about 14201.3608150768. The cubic root of 201678649 is about 586.4351245303.

The spelling of 201678649 in words is "two hundred one million, six hundred seventy-eight thousand, six hundred forty-nine".