1221613 has 4 divisors (see below), whose sum is σ = 1231360. Its totient is φ = 1211868.

The previous prime is 1221601. The next prime is 1221631. The reversal of 1221613 is 3161221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221613 is a prime.

It is a Duffinian number.

1221613 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221653) 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, 4683 + ... + 4936.

It is an arithmetic number, because the mean of its divisors is an integer number (307840).

2^1221613 is an apocalyptic number.

It is an amenable number.

1221613 is a deficient number, since it is larger than the sum of its proper divisors (9747).

1221613 is an equidigital number, since it uses as much as digits as its factorization.

1221613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9746.

The product of its digits is 72, while the sum is 16.

The square root of 1221613 is about 1105.2660313246. The cubic root of 1221613 is about 106.9000434911.

Adding to 1221613 its reverse (3161221), we get a palindrome (4382834).

The spelling of 1221613 in words is "one million, two hundred twenty-one thousand, six hundred thirteen".