1221039378 has 48 divisors (see below), whose sum is σ = 2855938176. Its totient is φ = 374801760.

The previous prime is 1221039349. The next prime is 1221039383. The reversal of 1221039378 is 8739301221.

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 in 23 ways as a sum of consecutive naturals, for example, 94801 + ... + 106907.

It is an arithmetic number, because the mean of its divisors is an integer number (59498712).

Almost surely, 2^1221039378 is an apocalyptic number.

1221039378 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221039378, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1427969088).

1221039378 is an abundant number, since it is smaller than the sum of its proper divisors (1634898798).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221039378 is a wasteful number, since it uses less digits than its factorization.

1221039378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12559 (or 12556 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 1221039378 is about 34943.3738783192. The cubic root of 1221039378 is about 1068.8330883592.

The spelling of 1221039378 in words is "one billion, two hundred twenty-one million, thirty-nine thousand, three hundred seventy-eight".