261651456 has 264 divisors, whose sum is σ = 862196400. Its totient is φ = 75694080.

The previous prime is 261651421. The next prime is 261651461. The reversal of 261651456 is 654156162.

It is a tau number, because it is divible by the number of its divisors (264).

It is a super-2 number, since 2×261651456² = 136922968853839872, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 261651456.

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, 2939860 + ... + 2939948.

Almost surely, 2^261651456 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 261651456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (431098200).

261651456 is an abundant number, since it is smaller than the sum of its proper divisors (600544944).

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

261651456 is a wasteful number, since it uses less digits than its factorization.

261651456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 134 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 261651456 is about 16175.6439129946. The cubic root of 261651456 is about 639.5989153615.

The spelling of 261651456 in words is "two hundred sixty-one million, six hundred fifty-one thousand, four hundred fifty-six".