661710620 has 12 divisors (see below), whose sum is σ = 1389592344. Its totient is φ = 264684240.

The previous prime is 661710571. The next prime is 661710629. The reversal of 661710620 is 26017166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661710629) 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, 16542746 + ... + 16542785.

It is an arithmetic number, because the mean of its divisors is an integer number (115799362).

Almost surely, 2^661710620 is an apocalyptic number.

It is an amenable number.

661710620 is an abundant number, since it is smaller than the sum of its proper divisors (727881724).

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

661710620 is a wasteful number, since it uses less digits than its factorization.

661710620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33085540 (or 33085538 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 661710620 is about 25723.7365093021. The cubic root of 661710620 is about 871.4103253880.

Adding to 661710620 its reverse (26017166), we get a palindrome (687727786).

The spelling of 661710620 in words is "six hundred sixty-one million, seven hundred ten thousand, six hundred twenty".