261229860 has 336 divisors, whose sum is σ = 925464960. Its totient is φ = 61585920.

The previous prime is 261229847. The next prime is 261229861. The reversal of 261229860 is 68922162.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (261229861) by changing a digit.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 6371440 + ... + 6371480.

It is an arithmetic number, because the mean of its divisors is an integer number (2754360).

Almost surely, 2^261229860 is an apocalyptic number.

261229860 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 261229860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (462732480).

261229860 is an abundant number, since it is smaller than the sum of its proper divisors (664235100).

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

261229860 is a wasteful number, since it uses less digits than its factorization.

261229860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110 (or 93 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 261229860 is about 16162.6068441944. The cubic root of 261229860 is about 639.2552045494.

The spelling of 261229860 in words is "two hundred sixty-one million, two hundred twenty-nine thousand, eight hundred sixty".