1221515 has 4 divisors (see below), whose sum is σ = 1465824. Its totient is φ = 977208.

The previous prime is 1221503. The next prime is 1221523. The reversal of 1221515 is 5151221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5151221 = 17 ⋅303013.

It is a cyclic number.

It is not a de Polignac number, because 1221515 - 2⁴ = 1221499 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221493 and 1221502.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122147 + ... + 122156.

It is an arithmetic number, because the mean of its divisors is an integer number (366456).

2^1221515 is an apocalyptic number.

1221515 is a deficient number, since it is larger than the sum of its proper divisors (244309).

1221515 is an equidigital number, since it uses as much as digits as its factorization.

1221515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244308.

The product of its digits is 100, while the sum is 17.

The square root of 1221515 is about 1105.2216972174. The cubic root of 1221515 is about 106.8971848432.

Adding to 1221515 its reverse (5151221), we get a palindrome (6372736).

The spelling of 1221515 in words is "one million, two hundred twenty-one thousand, five hundred fifteen".