203400991 has 2 divisors, whose sum is σ = 203400992. Its totient is φ = 203400990.

The previous prime is 203400979. The next prime is 203400997. The reversal of 203400991 is 199004302.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 203400991 - 2¹³ = 203392799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (203400997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101700495 + 101700496.

It is an arithmetic number, because the mean of its divisors is an integer number (101700496).

Almost surely, 2^203400991 is an apocalyptic number.

203400991 is a deficient number, since it is larger than the sum of its proper divisors (1).

203400991 is an equidigital number, since it uses as much as digits as its factorization.

203400991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 203400991 is about 14261.8719318328. The cubic root of 203400991 is about 588.0997861948.

It can be divided in two parts, 20340099 and 1, that added together give a square (20340100 = 4510²).

The spelling of 203400991 in words is "two hundred three million, four hundred thousand, nine hundred ninety-one".