2215312661 has 4 divisors (see below), whose sum is σ = 2251629324. Its totient is φ = 2178996000.

The previous prime is 2215312651. The next prime is 2215312691. The reversal of 2215312661 is 1662135122.

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 525280561 + 1690032100 = 22919^2 + 41110^2 .

It is a cyclic number.

It is not a de Polignac number, because 2215312661 - 2¹⁴ = 2215296277 is a prime.

It is a super-2 number, since 2×2215312661² = 9815220371973801842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2215312651) 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, 18158240 + ... + 18158361.

It is an arithmetic number, because the mean of its divisors is an integer number (562907331).

Almost surely, 2^2215312661 is an apocalyptic number.

It is an amenable number.

2215312661 is a deficient number, since it is larger than the sum of its proper divisors (36316663).

2215312661 is an equidigital number, since it uses as much as digits as its factorization.

2215312661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36316662.

The product of its digits is 4320, while the sum is 29.

The square root of 2215312661 is about 47067.1080586008. The cubic root of 2215312661 is about 1303.6019753028.

Adding to 2215312661 its reverse (1662135122), we get a palindrome (3877447783).

The spelling of 2215312661 in words is "two billion, two hundred fifteen million, three hundred twelve thousand, six hundred sixty-one".