261776736 has 144 divisors (see below), whose sum is σ = 829679760. Its totient is φ = 77736960.

The previous prime is 261776729. The next prime is 261776743. The reversal of 261776736 is 637677162.

261776736 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261776729) and next prime (261776743).

It is a tau number, because it is divible by the number of its divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 261776691 and 261776700.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 107371 + ... + 109781.

It is an arithmetic number, because the mean of its divisors is an integer number (5761665).

Almost surely, 2^261776736 is an apocalyptic number.

261776736 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261776736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (414839880).

261776736 is an abundant number, since it is smaller than the sum of its proper divisors (567903024).

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

261776736 is a wasteful number, since it uses less digits than its factorization.

261776736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2469 (or 2458 counting only the distinct ones).

The product of its digits is 444528, while the sum is 45.

The square root of 261776736 is about 16179.5159383710. The cubic root of 261776736 is about 639.7009801058.

The spelling of 261776736 in words is "two hundred sixty-one million, seven hundred seventy-six thousand, seven hundred thirty-six".