121557888 has 128 divisors (see below), whose sum is σ = 380052000. Its totient is φ = 38117376.

The previous prime is 121557857. The next prime is 121557889. The reversal of 121557888 is 888755121.

121557888 is a `hidden beast` number, since 12 + 1 + 557 + 8 + 88 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121557889) 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, 57718 + ... + 59786.

Almost surely, 2^121557888 is an apocalyptic number.

121557888 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121557888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (190026000).

121557888 is an abundant number, since it is smaller than the sum of its proper divisors (258494112).

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

121557888 is a wasteful number, since it uses less digits than its factorization.

121557888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109 (or 2091 counting only the distinct ones).

The product of its digits is 179200, while the sum is 45.

The square root of 121557888 is about 11025.3293828348. The cubic root of 121557888 is about 495.3677340899.

It can be divided in two parts, 121 and 557888, that added together give a square (558009 = 747²).

The spelling of 121557888 in words is "one hundred twenty-one million, five hundred fifty-seven thousand, eight hundred eighty-eight".