1220123491 has 2 divisors, whose sum is σ = 1220123492. Its totient is φ = 1220123490.

The previous prime is 1220123453. The next prime is 1220123537. The reversal of 1220123491 is 1943210221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1220123491 - 2¹¹ = 1220121443 is a prime.

It is not a weakly prime, because it can be changed into another prime (1220123291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610061745 + 610061746.

It is an arithmetic number, because the mean of its divisors is an integer number (610061746).

Almost surely, 2^1220123491 is an apocalyptic number.

1220123491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220123491 is an equidigital number, since it uses as much as digits as its factorization.

1220123491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 1220123491 is about 34930.2661169365. The cubic root of 1220123491 is about 1068.5657818847.

The spelling of 1220123491 in words is "one billion, two hundred twenty million, one hundred twenty-three thousand, four hundred ninety-one".