661121244 has 96 divisors (see below), whose sum is σ = 1964390400. Its totient is φ = 188360640.

The previous prime is 661121203. The next prime is 661121249. The reversal of 661121244 is 442121166.

661121244 is a `hidden beast` number, since 6 + 611 + 2 + 1 + 2 + 44 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661121249) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 324822 + ... + 326850.

It is an arithmetic number, because the mean of its divisors is an integer number (20462400).

Almost surely, 2^661121244 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 661121244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (982195200).

661121244 is an abundant number, since it is smaller than the sum of its proper divisors (1303269156).

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

661121244 is a wasteful number, since it uses less digits than its factorization.

661121244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2480 (or 2472 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 661121244 is about 25712.2780787701. The cubic root of 661121244 is about 871.1515310482.

The spelling of 661121244 in words is "six hundred sixty-one million, one hundred twenty-one thousand, two hundred forty-four".