651616728 has 64 divisors (see below), whose sum is σ = 1879887360. Its totient is φ = 184363776.

The previous prime is 651616697. The next prime is 651616729. The reversal of 651616728 is 827616156.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 651616728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651616729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1525 + ... + 36132.

It is an arithmetic number, because the mean of its divisors is an integer number (29373240).

Almost surely, 2^651616728 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 651616728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (939943680).

651616728 is an abundant number, since it is smaller than the sum of its proper divisors (1228270632).

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

651616728 is a wasteful number, since it uses less digits than its factorization.

651616728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37776 (or 37772 counting only the distinct ones).

The product of its digits is 120960, while the sum is 42.

The square root of 651616728 is about 25526.7845213611. The cubic root of 651616728 is about 866.9567020066.

The spelling of 651616728 in words is "six hundred fifty-one million, six hundred sixteen thousand, seven hundred twenty-eight".