661651312 has 60 divisors (see below), whose sum is σ = 1496649000. Its totient is φ = 282538368.

The previous prime is 661651283. The next prime is 661651351. The reversal of 661651312 is 213156166.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 239314 + ... + 242062.

It is an arithmetic number, because the mean of its divisors is an integer number (24944150).

Almost surely, 2^661651312 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 661651312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (748324500).

661651312 is an abundant number, since it is smaller than the sum of its proper divisors (834997688).

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

661651312 is a wasteful number, since it uses less digits than its factorization.

661651312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3078 (or 3065 counting only the distinct ones).

The product of its digits is 6480, while the sum is 31.

The square root of 661651312 is about 25722.5836960442. The cubic root of 661651312 is about 871.3842902673.

The spelling of 661651312 in words is "six hundred sixty-one million, six hundred fifty-one thousand, three hundred twelve".