661608860 has 24 divisors (see below), whose sum is σ = 1515686256. Its totient is φ = 240584960.

The previous prime is 661608821. The next prime is 661608863. The reversal of 661608860 is 68806166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661608863) 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, 1503437 + ... + 1503876.

It is an arithmetic number, because the mean of its divisors is an integer number (63153594).

Almost surely, 2^661608860 is an apocalyptic number.

It is an amenable number.

661608860 is an abundant number, since it is smaller than the sum of its proper divisors (854077396).

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

661608860 is a wasteful number, since it uses less digits than its factorization.

661608860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3007333 (or 3007331 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 661608860 is about 25721.7584935401. The cubic root of 661608860 is about 871.3656536650.

The spelling of 661608860 in words is "six hundred sixty-one million, six hundred eight thousand, eight hundred sixty".