661025320 has 32 divisors (see below), whose sum is σ = 1490027400. Its totient is φ = 263926528.

The previous prime is 661025303. The next prime is 661025327. The reversal of 661025320 is 23520166.

It can be written as a sum of positive squares in 4 ways, for example, as 175880644 + 485144676 = 13262^2 + 22026^2 .

It is a super-2 number, since 2×661025320² = 873908947362204800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661025327) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7446 + ... + 37114.

Almost surely, 2^661025320 is an apocalyptic number.

It is an amenable number.

661025320 is an abundant number, since it is smaller than the sum of its proper divisors (829002080).

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

661025320 is a wasteful number, since it uses less digits than its factorization.

661025320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30237 (or 30233 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 661025320 is about 25710.4126765791. The cubic root of 661025320 is about 871.1093963756.

Adding to 661025320 its reverse (23520166), we get a palindrome (684545486).

The spelling of 661025320 in words is "six hundred sixty-one million, twenty-five thousand, three hundred twenty".