1221272780 has 48 divisors (see below), whose sum is σ = 3156525120. Its totient is φ = 386512128.

The previous prime is 1221272761. The next prime is 1221272797. The reversal of 1221272780 is 872721221.

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 15 ways as a sum of consecutive naturals, for example, 333695 + ... + 337334.

It is an arithmetic number, because the mean of its divisors is an integer number (65760940).

Almost surely, 2^1221272780 is an apocalyptic number.

1221272780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221272780 is an abundant number, since it is smaller than the sum of its proper divisors (1935252340).

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

1221272780 is a wasteful number, since it uses less digits than its factorization.

1221272780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671058 (or 671056 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 32.

The square root of 1221272780 is about 34946.7134363162. The cubic root of 1221272780 is about 1068.9011865962.

The spelling of 1221272780 in words is "one billion, two hundred twenty-one million, two hundred seventy-two thousand, seven hundred eighty".