261042720 has 96 divisors (see below), whose sum is σ = 834660288. Its totient is φ = 68563968.

The previous prime is 261042713. The next prime is 261042757. The reversal of 261042720 is 27240162.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-3 number, since 3×261042720³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28102 + ... + 36218.

It is an arithmetic number, because the mean of its divisors is an integer number (8694378).

Almost surely, 2^261042720 is an apocalyptic number.

261042720 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 261042720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (417330144).

261042720 is an abundant number, since it is smaller than the sum of its proper divisors (573617568).

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

261042720 is a wasteful number, since it uses less digits than its factorization.

261042720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8202 (or 8194 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 261042720 is about 16156.8165181140. The cubic root of 261042720 is about 639.1025180771.

Adding to 261042720 its reverse (27240162), we get a palindrome (288282882).

The spelling of 261042720 in words is "two hundred sixty-one million, forty-two thousand, seven hundred twenty".