661037320 has 16 divisors (see below), whose sum is σ = 1487334060. Its totient is φ = 264414912.

The previous prime is 661037317. The next prime is 661037327. The reversal of 661037320 is 23730166.

It can be written as a sum of positive squares in 2 ways, for example, as 623900484 + 37136836 = 24978^2 + 6094^2 .

It is not an unprimeable number, because it can be changed into a prime (661037327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8262927 + ... + 8263006.

Almost surely, 2^661037320 is an apocalyptic number.

It is an amenable number.

661037320 is an abundant number, since it is smaller than the sum of its proper divisors (826296740).

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

661037320 is a wasteful number, since it uses less digits than its factorization.

661037320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16525944 (or 16525940 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 28.

The square root of 661037320 is about 25710.6460440029. The cubic root of 661037320 is about 871.1146676056.

Adding to 661037320 its reverse (23730166), we get a palindrome (684767486).

The spelling of 661037320 in words is "six hundred sixty-one million, thirty-seven thousand, three hundred twenty".