261501312 has 32 divisors (see below), whose sum is σ = 694613880. Its totient is φ = 87166976.

The previous prime is 261501301. The next prime is 261501319. The reversal of 261501312 is 213105162.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261501319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 340113 + ... + 340880.

Almost surely, 2^261501312 is an apocalyptic number.

It is an amenable number.

261501312 is an abundant number, since it is smaller than the sum of its proper divisors (433112568).

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

261501312 is an equidigital number, since it uses as much as digits as its factorization.

261501312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681010 (or 680998 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 261501312 is about 16171.0021952877. The cubic root of 261501312 is about 639.4765511604.

Adding to 261501312 its reverse (213105162), we get a palindrome (474606474).

The spelling of 261501312 in words is "two hundred sixty-one million, five hundred one thousand, three hundred twelve".