121561019 has 2 divisors, whose sum is σ = 121561020. Its totient is φ = 121561018.

The previous prime is 121561009. The next prime is 121561039. The reversal of 121561019 is 910165121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121561019 - 2²⁰ = 120512443 is a prime.

It is a super-2 number, since 2×121561019² = 29554162680636722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (121561009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60780509 + 60780510.

It is an arithmetic number, because the mean of its divisors is an integer number (60780510).

Almost surely, 2^121561019 is an apocalyptic number.

121561019 is a deficient number, since it is larger than the sum of its proper divisors (1).

121561019 is an equidigital number, since it uses as much as digits as its factorization.

121561019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 26.

The square root of 121561019 is about 11025.4713731432. The cubic root of 121561019 is about 495.3719871611.

The spelling of 121561019 in words is "one hundred twenty-one million, five hundred sixty-one thousand, nineteen".