261905603 has 2 divisors, whose sum is σ = 261905604. Its totient is φ = 261905602.

The previous prime is 261905597. The next prime is 261905617. The reversal of 261905603 is 306509162.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261905603 - 2²² = 257711299 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261905603.

It is not a weakly prime, because it can be changed into another prime (261905653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130952801 + 130952802.

It is an arithmetic number, because the mean of its divisors is an integer number (130952802).

Almost surely, 2^261905603 is an apocalyptic number.

261905603 is a deficient number, since it is larger than the sum of its proper divisors (1).

261905603 is an equidigital number, since it uses as much as digits as its factorization.

261905603 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 261905603 is about 16183.4978604750. The cubic root of 261905603 is about 639.8059331839.

The spelling of 261905603 in words is "two hundred sixty-one million, nine hundred five thousand, six hundred three".