261798480 has 210 divisors, whose sum is σ = 926428986. Its totient is φ = 68770944.

The previous prime is 261798469. The next prime is 261798497. The reversal of 261798480 is 84897162.

It can be written as a sum of positive squares in only one way, i.e., 209438784 + 52359696 = 14472^2 + 7236^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 3907407 + ... + 3907473.

Almost surely, 2^261798480 is an apocalyptic number.

261798480 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 261798480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (463214493).

261798480 is an abundant number, since it is smaller than the sum of its proper divisors (664630506).

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

261798480 is an frugal number, since it uses more digits than its factorization.

261798480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 261798480 is about 16180.1878851885. The cubic root of 261798480 is about 639.7186914746.

Multiplying 261798480 by its sum of digits (45), we get a square (11780931600 = 108540²).

261798480 divided by its sum of digits (45) gives a square (5817744 = 2412²).

The spelling of 261798480 in words is "two hundred sixty-one million, seven hundred ninety-eight thousand, four hundred eighty".