661628672 has 72 divisors (see below), whose sum is σ = 1415805216. Its totient is φ = 307777536.

The previous prime is 661628663. The next prime is 661628683. The reversal of 661628672 is 276826166.

661628672 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×661628672² = 875504999224967168, which contains 22 as substring.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 216338 + ... + 219374.

Almost surely, 2^661628672 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 661628672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (707902608).

661628672 is an abundant number, since it is smaller than the sum of its proper divisors (754176544).

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

661628672 is a wasteful number, since it uses less digits than its factorization.

661628672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3113 (or 3099 counting only the distinct ones).

The product of its digits is 290304, while the sum is 44.

The square root of 661628672 is about 25722.1436120709. The cubic root of 661628672 is about 871.3743513135.

The spelling of 661628672 in words is "six hundred sixty-one million, six hundred twenty-eight thousand, six hundred seventy-two".