1221400613 has 4 divisors (see below), whose sum is σ = 1232815680. Its totient is φ = 1209985548.

The previous prime is 1221400603. The next prime is 1221400637. The reversal of 1221400613 is 3160041221.

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, and also an emirpimes, since its reverse is a distinct semiprime: 3160041221 = 19 ⋅166317959.

It is a cyclic number.

It is not a de Polignac number, because 1221400613 - 2²⁰ = 1220352037 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221400603) 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, 5707373 + ... + 5707586.

It is an arithmetic number, because the mean of its divisors is an integer number (308203920).

Almost surely, 2^1221400613 is an apocalyptic number.

It is an amenable number.

1221400613 is a deficient number, since it is larger than the sum of its proper divisors (11415067).

1221400613 is a wasteful number, since it uses less digits than its factorization.

1221400613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11415066.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 1221400613 is about 34948.5423587308. The cubic root of 1221400613 is about 1068.9384799512.

Adding to 1221400613 its reverse (3160041221), we get a palindrome (4381441834).

The spelling of 1221400613 in words is "one billion, two hundred twenty-one million, four hundred thousand, six hundred thirteen".