1216515501 has 12 divisors (see below), whose sum is σ = 1758030300. Its totient is φ = 810622080.

The previous prime is 1216515499. The next prime is 1216515589. The reversal of 1216515501 is 1055156121.

1216515501 is a `hidden beast` number, since 1 + 2 + 1 + 651 + 5 + 5 + 0 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1068309225 + 148206276 = 32685^2 + 12174^2 .

It is not a de Polignac number, because 1216515501 - 2¹ = 1216515499 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216515301) 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 11 ways as a sum of consecutive naturals, for example, 11826 + ... + 50723.

It is an arithmetic number, because the mean of its divisors is an integer number (146502525).

Almost surely, 2^1216515501 is an apocalyptic number.

It is an amenable number.

1216515501 is a deficient number, since it is larger than the sum of its proper divisors (541514799).

1216515501 is a wasteful number, since it uses less digits than its factorization.

1216515501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64716 (or 64713 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 27.

The square root of 1216515501 is about 34878.5822676324. The cubic root of 1216515501 is about 1067.5114675351.

The spelling of 1216515501 in words is "one billion, two hundred sixteen million, five hundred fifteen thousand, five hundred one".