261365646 has 8 divisors (see below), whose sum is σ = 522731304. Its totient is φ = 87121880.

The previous prime is 261365639. The next prime is 261365647. The reversal of 261365646 is 646563162.

It is a sphenic number, since it is the product of 3 distinct primes.

261365646 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261365647) 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, 21780465 + ... + 21780476.

It is an arithmetic number, because the mean of its divisors is an integer number (65341413).

Almost surely, 2^261365646 is an apocalyptic number.

261365646 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261365646 is a wasteful number, since it uses less digits than its factorization.

261365646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43560946.

The product of its digits is 155520, while the sum is 39.

The square root of 261365646 is about 16166.8069203538. The cubic root of 261365646 is about 639.3659459373.

The spelling of 261365646 in words is "two hundred sixty-one million, three hundred sixty-five thousand, six hundred forty-six".