1221425643 has 8 divisors (see below), whose sum is σ = 1632456000. Its totient is φ = 812339528.

The previous prime is 1221425641. The next prime is 1221425669. The reversal of 1221425643 is 3465241221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221425643 - 2¹ = 1221425641 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221425643.

It is not an unprimeable number, because it can be changed into a prime (1221425641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 484593 + ... + 487106.

It is an arithmetic number, because the mean of its divisors is an integer number (204057000).

Almost surely, 2^1221425643 is an apocalyptic number.

1221425643 is a deficient number, since it is larger than the sum of its proper divisors (411030357).

1221425643 is an equidigital number, since it uses as much as digits as its factorization.

1221425643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 972121.

The product of its digits is 11520, while the sum is 30.

The square root of 1221425643 is about 34948.9004548069. The cubic root of 1221425643 is about 1068.9457817726.

Adding to 1221425643 its reverse (3465241221), we get a palindrome (4686666864).

The spelling of 1221425643 in words is "one billion, two hundred twenty-one million, four hundred twenty-five thousand, six hundred forty-three".