204253991 has 2 divisors, whose sum is σ = 204253992. Its totient is φ = 204253990.

The previous prime is 204253981. The next prime is 204253993. The reversal of 204253991 is 199352402.

204253991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-204253991 is a prime.

Together with 204253993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204253993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102126995 + 102126996.

It is an arithmetic number, because the mean of its divisors is an integer number (102126996).

Almost surely, 2^204253991 is an apocalyptic number.

204253991 is a deficient number, since it is larger than the sum of its proper divisors (1).

204253991 is an equidigital number, since it uses as much as digits as its factorization.

204253991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 204253991 is about 14291.7455546900. The cubic root of 204253991 is about 588.9207417062.

The spelling of 204253991 in words is "two hundred four million, two hundred fifty-three thousand, nine hundred ninety-one".