1221211786 has 16 divisors (see below), whose sum is σ = 1863658368. Its totient is φ = 600048400.

The previous prime is 1221211781. The next prime is 1221211787. The reversal of 1221211786 is 6871121221.

It is not an unprimeable number, because it can be changed into a prime (1221211781) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 30336 + ... + 57988.

It is an arithmetic number, because the mean of its divisors is an integer number (116478648).

Almost surely, 2^1221211786 is an apocalyptic number.

1221211786 is a deficient number, since it is larger than the sum of its proper divisors (642446582).

1221211786 is a wasteful number, since it uses less digits than its factorization.

1221211786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28037.

The product of its digits is 2688, while the sum is 31.

The square root of 1221211786 is about 34945.8407539438. The cubic root of 1221211786 is about 1068.8833915970.

The spelling of 1221211786 in words is "one billion, two hundred twenty-one million, two hundred eleven thousand, seven hundred eighty-six".