1221923539 has 2 divisors, whose sum is σ = 1221923540. Its totient is φ = 1221923538.

The previous prime is 1221923519. The next prime is 1221923543. The reversal of 1221923539 is 9353291221.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221923539 - 2⁷ = 1221923411 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221923498 and 1221923507.

It is not a weakly prime, because it can be changed into another prime (1221923509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610961769 + 610961770.

It is an arithmetic number, because the mean of its divisors is an integer number (610961770).

Almost surely, 2^1221923539 is an apocalyptic number.

1221923539 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221923539 is an equidigital number, since it uses as much as digits as its factorization.

1221923539 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29160, while the sum is 37.

The square root of 1221923539 is about 34956.0229288173. The cubic root of 1221923539 is about 1069.0910086586.

The spelling of 1221923539 in words is "one billion, two hundred twenty-one million, nine hundred twenty-three thousand, five hundred thirty-nine".