261600551 has 6 divisors (see below), whose sum is σ = 273469560. Its totient is φ = 250226108.

The previous prime is 261600529. The next prime is 261600553. The reversal of 261600551 is 155006162.

It is not a de Polignac number, because 261600551 - 2⁶ = 261600487 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261600551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261600553) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 246731 + ... + 247788.

It is an arithmetic number, because the mean of its divisors is an integer number (45578260).

Almost surely, 2^261600551 is an apocalyptic number.

261600551 is a deficient number, since it is larger than the sum of its proper divisors (11869009).

261600551 is an equidigital number, since it uses as much as digits as its factorization.

261600551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494565 (or 494542 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 261600551 is about 16174.0703287701. The cubic root of 261600551 is about 639.5574341038.

The spelling of 261600551 in words is "two hundred sixty-one million, six hundred thousand, five hundred fifty-one".