261506243 has 2 divisors, whose sum is σ = 261506244. Its totient is φ = 261506242.

The previous prime is 261506239. The next prime is 261506249. The reversal of 261506243 is 342605162.

261506243 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 is a cyclic number.

It is not a de Polignac number, because 261506243 - 2² = 261506239 is a prime.

It is not a weakly prime, because it can be changed into another prime (261506249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130753121 + 130753122.

It is an arithmetic number, because the mean of its divisors is an integer number (130753122).

Almost surely, 2^261506243 is an apocalyptic number.

261506243 is a deficient number, since it is larger than the sum of its proper divisors (1).

261506243 is an equidigital number, since it uses as much as digits as its factorization.

261506243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 261506243 is about 16171.1546588362. The cubic root of 261506243 is about 639.4805705655.

The spelling of 261506243 in words is "two hundred sixty-one million, five hundred six thousand, two hundred forty-three".