261045663 has 4 divisors (see below), whose sum is σ = 348060888. Its totient is φ = 174030440.

The previous prime is 261045623. The next prime is 261045667. The reversal of 261045663 is 366540162.

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

It is a cyclic number.

It is not a de Polignac number, because 261045663 - 2¹⁶ = 260980127 is a prime.

It is a super-2 number, since 2×261045663² = 136289676342219138, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261045667) 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, 43507608 + ... + 43507613.

It is an arithmetic number, because the mean of its divisors is an integer number (87015222).

Almost surely, 2^261045663 is an apocalyptic number.

261045663 is a deficient number, since it is larger than the sum of its proper divisors (87015225).

261045663 is an equidigital number, since it uses as much as digits as its factorization.

261045663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87015224.

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 261045663 is about 16156.9075939674. The cubic root of 261045663 is about 639.1049198190.

The spelling of 261045663 in words is "two hundred sixty-one million, forty-five thousand, six hundred sixty-three".