261422720 has 96 divisors (see below), whose sum is σ = 677015820. Its totient is φ = 96485376.

The previous prime is 261422701. The next prime is 261422731. The reversal of 261422720 is 27224162.

It can be written as a sum of positive squares in 6 ways, for example, as 92006464 + 169416256 = 9592^2 + 13016^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 261422720.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 106952 + ... + 109368.

Almost surely, 2^261422720 is an apocalyptic number.

261422720 is a gapful number since it is divisible by the number (20) 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 261422720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (338507910).

261422720 is an abundant number, since it is smaller than the sum of its proper divisors (415593100).

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

261422720 is a wasteful number, since it uses less digits than its factorization.

261422720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2462 (or 2437 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 261422720 is about 16168.5719839447. The cubic root of 261422720 is about 639.4124816581.

Adding to 261422720 its reverse (27224162), we get a palindrome (288646882).

The spelling of 261422720 in words is "two hundred sixty-one million, four hundred twenty-two thousand, seven hundred twenty".