1216220761 has 16 divisors (see below), whose sum is σ = 1498815360. Its totient is φ = 963515520.

The previous prime is 1216220741. The next prime is 1216220767. The reversal of 1216220761 is 1670226121.

It is a cyclic number.

It is not a de Polignac number, because 1216220761 - 2⁷ = 1216220633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1216220767) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106066 + ... + 116971.

It is an arithmetic number, because the mean of its divisors is an integer number (93675960).

Almost surely, 2^1216220761 is an apocalyptic number.

It is an amenable number.

1216220761 is a deficient number, since it is larger than the sum of its proper divisors (282594599).

1216220761 is a wasteful number, since it uses less digits than its factorization.

1216220761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223104.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 1216220761 is about 34874.3567825989. The cubic root of 1216220761 is about 1067.4252475778.

Adding to 1216220761 its reverse (1670226121), we get a palindrome (2886446882).

It can be divided in two parts, 12162 and 20761, that added together give a palindrome (32923).

The spelling of 1216220761 in words is "one billion, two hundred sixteen million, two hundred twenty thousand, seven hundred sixty-one".