261751616 has 56 divisors (see below), whose sum is σ = 609697536. Its totient is φ = 109140480.

The previous prime is 261751591. The next prime is 261751627. The reversal of 261751616 is 616157162.

It is a tau number, because it is divible by the number of its divisors (56).

It is a super-2 number, since 2×261751616² = 137027816957222912, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8681 + ... + 24471.

It is an arithmetic number, because the mean of its divisors is an integer number (10887456).

Almost surely, 2^261751616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261751616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304848768).

261751616 is an abundant number, since it is smaller than the sum of its proper divisors (347945920).

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

261751616 is a wasteful number, since it uses less digits than its factorization.

261751616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15847 (or 15837 counting only the distinct ones).

The product of its digits is 15120, while the sum is 35.

The square root of 261751616 is about 16178.7396295262. The cubic root of 261751616 is about 639.6805176271.

The spelling of 261751616 in words is "two hundred sixty-one million, seven hundred fifty-one thousand, six hundred sixteen".