1661213315 has 16 divisors (see below), whose sum is σ = 2004340800. Its totient is φ = 1321736832.

The previous prime is 1661213311. The next prime is 1661213317. The reversal of 1661213315 is 5133121661.

It is a cyclic number.

It is not a de Polignac number, because 1661213315 - 2² = 1661213311 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661213311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 817721 + ... + 819749.

It is an arithmetic number, because the mean of its divisors is an integer number (125271300).

Almost surely, 2^1661213315 is an apocalyptic number.

1661213315 is a deficient number, since it is larger than the sum of its proper divisors (343127485).

1661213315 is a wasteful number, since it uses less digits than its factorization.

1661213315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2846.

The product of its digits is 3240, while the sum is 29.

The square root of 1661213315 is about 40757.9846778518. The cubic root of 1661213315 is about 1184.3365558772.

Adding to 1661213315 its reverse (5133121661), we get a palindrome (6794334976).

The spelling of 1661213315 in words is "one billion, six hundred sixty-one million, two hundred thirteen thousand, three hundred fifteen".