261099216 has 120 divisors (see below), whose sum is σ = 879120320. Its totient is φ = 70668288.

The previous prime is 261099199. The next prime is 261099217. The reversal of 261099216 is 612990162.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261099217) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12336 + ... + 25968.

Almost surely, 2^261099216 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 261099216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (439560160).

261099216 is an abundant number, since it is smaller than the sum of its proper divisors (618021104).

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

261099216 is a wasteful number, since it uses less digits than its factorization.

261099216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13673 (or 13664 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 261099216 is about 16158.5647877527. The cubic root of 261099216 is about 639.1486205329.

The spelling of 261099216 in words is "two hundred sixty-one million, ninety-nine thousand, two hundred sixteen".