261961284 has 96 divisors (see below), whose sum is σ = 715509760. Its totient is φ = 73872000.

The previous prime is 261961277. The next prime is 261961319. The reversal of 261961284 is 482169162.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 90459 + ... + 93309.

Almost surely, 2^261961284 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 261961284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (357754880).

261961284 is an abundant number, since it is smaller than the sum of its proper divisors (453548476).

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

261961284 is a wasteful number, since it uses less digits than its factorization.

261961284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2921 (or 2919 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 261961284 is about 16185.2180708201. The cubic root of 261961284 is about 639.8512707781.

It can be divided in two parts, 2619 and 61284, that added together give a triangular number (63903 = T₃₅₇).

The spelling of 261961284 in words is "two hundred sixty-one million, nine hundred sixty-one thousand, two hundred eighty-four".