121021561 has 8 divisors (see below), whose sum is σ = 129697344. Its totient is φ = 112630320.

The previous prime is 121021543. The next prime is 121021573. The reversal of 121021561 is 165120121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121021561 - 2⁵ = 121021529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121021591) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70255 + ... + 71956.

It is an arithmetic number, because the mean of its divisors is an integer number (16212168).

Almost surely, 2^121021561 is an apocalyptic number.

It is an amenable number.

121021561 is a deficient number, since it is larger than the sum of its proper divisors (8675783).

121021561 is a wasteful number, since it uses less digits than its factorization.

121021561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142271.

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 121021561 is about 11000.9800017998. The cubic root of 121021561 is about 494.6381207044.

Adding to 121021561 its reverse (165120121), we get a palindrome (286141682).

The spelling of 121021561 in words is "one hundred twenty-one million, twenty-one thousand, five hundred sixty-one".