121161056509 has 16 divisors (see below), whose sum is σ = 128613703680. Its totient is φ = 113816994480.

The previous prime is 121161056431. The next prime is 121161056519. The reversal of 121161056509 is 905650161121.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121161056509 is a prime.

It is a super-2 number, since 2×121161056509² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121161056519) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4646502 + ... + 4672504.

It is an arithmetic number, because the mean of its divisors is an integer number (8038356480).

Almost surely, 2^121161056509 is an apocalyptic number.

121161056509 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

121161056509 is a deficient number, since it is larger than the sum of its proper divisors (7452647171).

121161056509 is a wasteful number, since it uses less digits than its factorization.

121161056509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28080.

The product of its (nonzero) digits is 16200, while the sum is 37.

The spelling of 121161056509 in words is "one hundred twenty-one billion, one hundred sixty-one million, fifty-six thousand, five hundred nine".