121663728 has 80 divisors (see below), whose sum is σ = 357789600. Its totient is φ = 39559680.

The previous prime is 121663699. The next prime is 121663739. The reversal of 121663728 is 827366121.

121663728 is a `hidden beast` number, since 1 + 2 + 16 + 637 + 2 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 121663692 and 121663701.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14278 + ... + 21146.

It is an arithmetic number, because the mean of its divisors is an integer number (4472370).

Almost surely, 2^121663728 is an apocalyptic number.

121663728 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 121663728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (178894800).

121663728 is an abundant number, since it is smaller than the sum of its proper divisors (236125872).

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

121663728 is a wasteful number, since it uses less digits than its factorization.

121663728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6927 (or 6915 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 121663728 is about 11030.1281950846. The cubic root of 121663728 is about 495.5114639962.

The spelling of 121663728 in words is "one hundred twenty-one million, six hundred sixty-three thousand, seven hundred twenty-eight".