121555644 has 96 divisors (see below), whose sum is σ = 358235136. Its totient is φ = 31257600.

The previous prime is 121555631. The next prime is 121555649. The reversal of 121555644 is 446555121.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121555649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30994 + ... + 34694.

It is an arithmetic number, because the mean of its divisors is an integer number (3731616).

Almost surely, 2^121555644 is an apocalyptic number.

121555644 is a gapful number since it is divisible by the number (14) 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 121555644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179117568).

121555644 is an abundant number, since it is smaller than the sum of its proper divisors (236679492).

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

121555644 is a wasteful number, since it uses less digits than its factorization.

121555644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3755 (or 3753 counting only the distinct ones).

The product of its digits is 24000, while the sum is 33.

The square root of 121555644 is about 11025.2276166980. The cubic root of 121555644 is about 495.3646858522.

The spelling of 121555644 in words is "one hundred twenty-one million, five hundred fifty-five thousand, six hundred forty-four".