1216061501 has 4 divisors (see below), whose sum is σ = 1220389404. Its totient is φ = 1211733600.

The previous prime is 1216061491. The next prime is 1216061519. The reversal of 1216061501 is 1051606121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 704849401 + 511212100 = 26549^2 + 22610^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216061501 - 2²² = 1211867197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216061531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2163530 + ... + 2164091.

It is an arithmetic number, because the mean of its divisors is an integer number (305097351).

Almost surely, 2^1216061501 is an apocalyptic number.

It is an amenable number.

1216061501 is a deficient number, since it is larger than the sum of its proper divisors (4327903).

1216061501 is an equidigital number, since it uses as much as digits as its factorization.

1216061501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4327902.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 1216061501 is about 34872.0733682412. The cubic root of 1216061501 is about 1067.3786536339.

Adding to 1216061501 its reverse (1051606121), we get a palindrome (2267667622).

The spelling of 1216061501 in words is "one billion, two hundred sixteen million, sixty-one thousand, five hundred one".