1221618135 has 16 divisors (see below), whose sum is σ = 1981365984. Its totient is φ = 642604032.

The previous prime is 1221618131. The next prime is 1221618143. The reversal of 1221618135 is 5318161221.

It is not a de Polignac number, because 1221618135 - 2² = 1221618131 is a prime.

It is a super-4 number, since 4×1221618135⁴ (a number of 37 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221618131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 556722 + ... + 558911.

It is an arithmetic number, because the mean of its divisors is an integer number (123835374).

Almost surely, 2^1221618135 is an apocalyptic number.

1221618135 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1221618135 is a deficient number, since it is larger than the sum of its proper divisors (759747849).

1221618135 is a wasteful number, since it uses less digits than its factorization.

1221618135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1115714.

The product of its digits is 2880, while the sum is 30.

The square root of 1221618135 is about 34951.6542526960. The cubic root of 1221618135 is about 1069.0019327424.

Adding to 1221618135 its reverse (5318161221), we get a palindrome (6539779356).

The spelling of 1221618135 in words is "one billion, two hundred twenty-one million, six hundred eighteen thousand, one hundred thirty-five".