1221748816 has 10 divisors (see below), whose sum is σ = 2367138362. Its totient is φ = 610874400.

The previous prime is 1221748807. The next prime is 1221748831. The reversal of 1221748816 is 6188471221.

It can be written as a sum of positive squares in only one way, i.e., 1218289216 + 3459600 = 34904^2 + 1860^2 .

It is a congruent number.

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, 38179635 + ... + 38179666.

Almost surely, 2^1221748816 is an apocalyptic number.

1221748816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1221748816 is a deficient number, since it is larger than the sum of its proper divisors (1145389546).

1221748816 is an equidigital number, since it uses as much as digits as its factorization.

1221748816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76359309 (or 76359303 counting only the distinct ones).

The product of its digits is 43008, while the sum is 40.

The square root of 1221748816 is about 34953.5236564213. The cubic root of 1221748816 is about 1069.0400497438.

The spelling of 1221748816 in words is "one billion, two hundred twenty-one million, seven hundred forty-eight thousand, eight hundred sixteen".