1215621328 has 10 divisors (see below), whose sum is σ = 2355266354. Its totient is φ = 607810656.

The previous prime is 1215621307. The next prime is 1215621353. The reversal of 1215621328 is 8231265121.

It can be written as a sum of positive squares in only one way, i.e., 918817344 + 296803984 = 30312^2 + 17228^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1215621328.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37988151 + ... + 37988182.

Almost surely, 2^1215621328 is an apocalyptic number.

It is an amenable number.

1215621328 is a deficient number, since it is larger than the sum of its proper divisors (1139645026).

1215621328 is an equidigital number, since it uses as much as digits as its factorization.

1215621328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75976341 (or 75976335 counting only the distinct ones).

The product of its digits is 5760, while the sum is 31.

The square root of 1215621328 is about 34865.7615433824. The cubic root of 1215621328 is about 1067.2498531407.

Adding to 1215621328 its reverse (8231265121), we get a palindrome (9446886449).

The spelling of 1215621328 in words is "one billion, two hundred fifteen million, six hundred twenty-one thousand, three hundred twenty-eight".