1220021623 has 4 divisors (see below), whose sum is σ = 1225803928. Its totient is φ = 1214239320.

The previous prime is 1220021519. The next prime is 1220021639. The reversal of 1220021623 is 3261200221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3261200221 = 229 ⋅14241049.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1220021623 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1220021623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220021653) 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, 2890836 + ... + 2891257.

It is an arithmetic number, because the mean of its divisors is an integer number (306450982).

Almost surely, 2^1220021623 is an apocalyptic number.

1220021623 is a deficient number, since it is larger than the sum of its proper divisors (5782305).

1220021623 is an equidigital number, since it uses as much as digits as its factorization.

1220021623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5782304.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 1220021623 is about 34928.8079241190. The cubic root of 1220021623 is about 1068.5360429035.

Adding to 1220021623 its reverse (3261200221), we get a palindrome (4481221844).

The spelling of 1220021623 in words is "one billion, two hundred twenty million, twenty-one thousand, six hundred twenty-three".