1531220728 has 32 divisors (see below), whose sum is σ = 2951418960. Its totient is φ = 744215040.

The previous prime is 1531220711. The next prime is 1531220767. The reversal of 1531220728 is 8270221351.

It is a self number, because there is not a number n which added to its sum of digits gives 1531220728.

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, 458023 + ... + 461353.

Almost surely, 2^1531220728 is an apocalyptic number.

It is an amenable number.

1531220728 is a deficient number, since it is larger than the sum of its proper divisors (1420198232).

1531220728 is a wasteful number, since it uses less digits than its factorization.

1531220728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4927 (or 4923 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 1531220728 is about 39130.8155805626. The cubic root of 1531220728 is about 1152.6017283860.

The spelling of 1531220728 in words is "one billion, five hundred thirty-one million, two hundred twenty thousand, seven hundred twenty-eight".