121001561 has 4 divisors (see below), whose sum is σ = 121026000. Its totient is φ = 120977124.

The previous prime is 121001533. The next prime is 121001599. The reversal of 121001561 is 165100121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165100121 = 401 ⋅411721.

It is a cyclic number.

It is not a de Polignac number, because 121001561 - 2⁶ = 121001497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121001161) 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, 1871 + ... + 15668.

It is an arithmetic number, because the mean of its divisors is an integer number (30256500).

Almost surely, 2^121001561 is an apocalyptic number.

It is an amenable number.

121001561 is a deficient number, since it is larger than the sum of its proper divisors (24439).

121001561 is an equidigital number, since it uses as much as digits as its factorization.

121001561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24438.

The product of its (nonzero) digits is 60, while the sum is 17.

The square root of 121001561 is about 11000.0709543166. The cubic root of 121001561 is about 494.6108712696.

Adding to 121001561 its reverse (165100121), we get a palindrome (286101682).

The spelling of 121001561 in words is "one hundred twenty-one million, one thousand, five hundred sixty-one".