661430320 has 160 divisors (see below), whose sum is σ = 1673892864. Its totient is φ = 242457600.

The previous prime is 661430317. The next prime is 661430321. The reversal of 661430320 is 23034166.

It is not an unprimeable number, because it can be changed into a prime (661430321) 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, 7968999 + ... + 7969081.

Almost surely, 2^661430320 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 661430320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (836946432).

661430320 is an abundant number, since it is smaller than the sum of its proper divisors (1012462544).

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

661430320 is a wasteful number, since it uses less digits than its factorization.

661430320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 25.

The square root of 661430320 is about 25718.2876568406. The cubic root of 661430320 is about 871.2872651440.

Adding to 661430320 its reverse (23034166), we get a palindrome (684464486).

The spelling of 661430320 in words is "six hundred sixty-one million, four hundred thirty thousand, three hundred twenty".