261611616 has 48 divisors (see below), whose sum is σ = 784836864. Its totient is φ = 74745984.

The previous prime is 261611599. The next prime is 261611621. The reversal of 261611616 is 616116162.

261611616 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×261611616² = 136881275252262912, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 193980 + ... + 195323.

It is an arithmetic number, because the mean of its divisors is an integer number (16350768).

Almost surely, 2^261611616 is an apocalyptic number.

It is an amenable number.

261611616 is an abundant number, since it is smaller than the sum of its proper divisors (523225248).

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

261611616 is a wasteful number, since it uses less digits than its factorization.

261611616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389323 (or 389315 counting only the distinct ones).

The product of its digits is 2592, while the sum is 30.

The square root of 261611616 is about 16174.4123849987. The cubic root of 261611616 is about 639.5664511633.

Adding to 261611616 its reverse (616116162), we get a palindrome (877727778).

The spelling of 261611616 in words is "two hundred sixty-one million, six hundred eleven thousand, six hundred sixteen".