1242120091 has 2 divisors, whose sum is σ = 1242120092. Its totient is φ = 1242120090.

The previous prime is 1242120067. The next prime is 1242120107. The reversal of 1242120091 is 1900212421.

It is a strong prime.

It is an emirp because it is prime and its reverse (1900212421) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1242120091 - 2¹¹ = 1242118043 is a prime.

It is not a weakly prime, because it can be changed into another prime (1242120001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621060045 + 621060046.

It is an arithmetic number, because the mean of its divisors is an integer number (621060046).

Almost surely, 2^1242120091 is an apocalyptic number.

1242120091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242120091 is an equidigital number, since it uses as much as digits as its factorization.

1242120091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 1242120091 is about 35243.7241363622. The cubic root of 1242120091 is about 1074.9490052608.

The spelling of 1242120091 in words is "one billion, two hundred forty-two million, one hundred twenty thousand, ninety-one".