261989316 has 60 divisors (see below), whose sum is σ = 690393088. Its totient is φ = 86628528.

The previous prime is 261989311. The next prime is 261989317. The reversal of 261989316 is 613989162.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (261989311) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 37965 + ... + 44331.

Almost surely, 2^261989316 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 261989316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (345196544).

261989316 is an abundant number, since it is smaller than the sum of its proper divisors (428403772).

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

261989316 is a wasteful number, since it uses less digits than its factorization.

261989316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6510 (or 6499 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 261989316 is about 16186.0840230119. The cubic root of 261989316 is about 639.8740930705.

The spelling of 261989316 in words is "two hundred sixty-one million, nine hundred eighty-nine thousand, three hundred sixteen".