1221015568 has 10 divisors (see below), whose sum is σ = 2365717694. Its totient is φ = 610507776.

The previous prime is 1221015557. The next prime is 1221015581. The reversal of 1221015568 is 8655101221.

It can be written as a sum of positive squares in only one way, i.e., 678498304 + 542517264 = 26048^2 + 23292^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38156721 + ... + 38156752.

Almost surely, 2^1221015568 is an apocalyptic number.

It is an amenable number.

1221015568 is a deficient number, since it is larger than the sum of its proper divisors (1144702126).

1221015568 is an equidigital number, since it uses as much as digits as its factorization.

1221015568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76313481 (or 76313475 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 31.

The square root of 1221015568 is about 34943.0331825959. The cubic root of 1221015568 is about 1068.8261409771.

Adding to 1221015568 its reverse (8655101221), we get a palindrome (9876116789).

The spelling of 1221015568 in words is "one billion, two hundred twenty-one million, fifteen thousand, five hundred sixty-eight".