1220654399 has 4 divisors (see below), whose sum is σ = 1262745960. Its totient is φ = 1178562840.

The previous prime is 1220654353. The next prime is 1220654401. The reversal of 1220654399 is 9934560221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9934560221 = 3467 ⋅2865463.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1220654399 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 (1220654999) 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, 21045737 + ... + 21045794.

It is an arithmetic number, because the mean of its divisors is an integer number (315686490).

Almost surely, 2^1220654399 is an apocalyptic number.

1220654399 is a deficient number, since it is larger than the sum of its proper divisors (42091561).

1220654399 is an equidigital number, since it uses as much as digits as its factorization.

1220654399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42091560.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 1220654399 is about 34937.8648317266. The cubic root of 1220654399 is about 1068.7207464879.

The spelling of 1220654399 in words is "one billion, two hundred twenty million, six hundred fifty-four thousand, three hundred ninety-nine".