661246320 has 320 divisors, whose sum is σ = 2482698240. Its totient is φ = 142331904.

The previous prime is 661246259. The next prime is 661246349. The reversal of 661246320 is 23642166.

661246320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4211682 + ... + 4211838.

It is an arithmetic number, because the mean of its divisors is an integer number (7758432).

Almost surely, 2^661246320 is an apocalyptic number.

661246320 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 661246320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1241349120).

661246320 is an abundant number, since it is smaller than the sum of its proper divisors (1821451920).

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

661246320 is a wasteful number, since it uses less digits than its factorization.

661246320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 306 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 30.

The square root of 661246320 is about 25714.7101869727. The cubic root of 661246320 is about 871.2064646322.

Adding to 661246320 its reverse (23642166), we get a palindrome (684888486).

The spelling of 661246320 in words is "six hundred sixty-one million, two hundred forty-six thousand, three hundred twenty".