642654728 has 8 divisors (see below), whose sum is σ = 1204977630. Its totient is φ = 321327360.

The previous prime is 642654667. The next prime is 642654751. The reversal of 642654728 is 827456246.

It can be written as a sum of positive squares in only one way, i.e., 394340164 + 248314564 = 19858^2 + 15758^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40165913 + ... + 40165928.

Almost surely, 2^642654728 is an apocalyptic number.

It is an amenable number.

642654728 is a deficient number, since it is larger than the sum of its proper divisors (562322902).

642654728 is a wasteful number, since it uses less digits than its factorization.

642654728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80331847 (or 80331843 counting only the distinct ones).

The product of its digits is 645120, while the sum is 44.

The square root of 642654728 is about 25350.6356527800. The cubic root of 642654728 is about 862.9637818813.

The spelling of 642654728 in words is "six hundred forty-two million, six hundred fifty-four thousand, seven hundred twenty-eight".