261744663 has 4 divisors (see below), whose sum is σ = 348992888. Its totient is φ = 174496440.

The previous prime is 261744653. The next prime is 261744671. The reversal of 261744663 is 366447162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 261744663 - 2⁴ = 261744647 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261744653) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43624108 + ... + 43624113.

It is an arithmetic number, because the mean of its divisors is an integer number (87248222).

Almost surely, 2^261744663 is an apocalyptic number.

261744663 is a deficient number, since it is larger than the sum of its proper divisors (87248225).

261744663 is an equidigital number, since it uses as much as digits as its factorization.

261744663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87248224.

The product of its digits is 145152, while the sum is 39.

The square root of 261744663 is about 16178.5247473310. The cubic root of 261744663 is about 639.6748535576.

The spelling of 261744663 in words is "two hundred sixty-one million, seven hundred forty-four thousand, six hundred sixty-three".