661098240 has 576 divisors, whose sum is σ = 2684344320. Its totient is φ = 152616960.

The previous prime is 661098199. The next prime is 661098241. The reversal of 661098240 is 42890166.

It is a tau number, because it is divible by the number of its divisors (576).

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

It is a junction number, because it is equal to n+sod(n) for n = 661098195 and 661098204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661098241) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 14065897 + ... + 14065943.

It is an arithmetic number, because the mean of its divisors is an integer number (4660320).

Almost surely, 2^661098240 is an apocalyptic number.

661098240 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661098240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1342172160).

661098240 is an abundant number, since it is smaller than the sum of its proper divisors (2023246080).

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

661098240 is a wasteful number, since it uses less digits than its factorization.

661098240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125 (or 105 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 661098240 is about 25711.8307399532. The cubic root of 661098240 is about 871.1414268994.

The spelling of 661098240 in words is "six hundred sixty-one million, ninety-eight thousand, two hundred forty".