1216011761 has 8 divisors (see below), whose sum is σ = 1280731200. Its totient is φ = 1151364240.

The previous prime is 1216011737. The next prime is 1216011767. The reversal of 1216011761 is 1671106121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1216011761 - 2³⁰ = 142269937 is a prime.

It is a super-2 number, since 2×1216011761² = 2957369205780642242, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1216011761.

It is not an unprimeable number, because it can be changed into a prime (1216011767) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18671 + ... + 52731.

It is an arithmetic number, because the mean of its divisors is an integer number (160091400).

Almost surely, 2^1216011761 is an apocalyptic number.

It is an amenable number.

1216011761 is a deficient number, since it is larger than the sum of its proper divisors (64719439).

1216011761 is a wasteful number, since it uses less digits than its factorization.

1216011761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35959.

The product of its (nonzero) digits is 504, while the sum is 26.

The square root of 1216011761 is about 34871.3601828205. The cubic root of 1216011761 is about 1067.3641006040.

Adding to 1216011761 its reverse (1671106121), we get a palindrome (2887117882).

The spelling of 1216011761 in words is "one billion, two hundred sixteen million, eleven thousand, seven hundred sixty-one".