121564128508554 has 64 divisors (see below), whose sum is σ = 260132581877760. Its totient is φ = 37757518096320.

The previous prime is 121564128508553. The next prime is 121564128508591. The reversal of 121564128508554 is 455805821465121.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a junction number, because it is equal to n+sod(n) for n = 121564128508494 and 121564128508503.

It is not an unprimeable number, because it can be changed into a prime (121564128508553) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 146615019 + ... + 147441825.

It is an arithmetic number, because the mean of its divisors is an integer number (4064571591840).

Almost surely, 2^{121564128508554} is an apocalyptic number.

121564128508554 is an abundant number, since it is smaller than the sum of its proper divisors (138568453369206).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121564128508554 is a wasteful number, since it uses less digits than its factorization.

121564128508554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 848035.

The product of its (nonzero) digits is 15360000, while the sum is 57.

The spelling of 121564128508554 in words is "one hundred twenty-one trillion, five hundred sixty-four billion, one hundred twenty-eight million, five hundred eight thousand, five hundred fifty-four".