121815648 has 144 divisors (see below), whose sum is σ = 360884160. Its totient is φ = 38953728.

The previous prime is 121815641. The next prime is 121815679. The reversal of 121815648 is 846518121.

121815648 is a `hidden beast` number, since 1 + 2 + 1 + 8 + 1 + 5 + 648 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-3 number, since 3×121815648³ (a number of 25 digits) contains 333 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121815641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1138411 + ... + 1138517.

It is an arithmetic number, because the mean of its divisors is an integer number (2506140).

Almost surely, 2^121815648 is an apocalyptic number.

121815648 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 121815648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (180442080).

121815648 is an abundant number, since it is smaller than the sum of its proper divisors (239068512).

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

121815648 is a wasteful number, since it uses less digits than its factorization.

121815648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249 (or 238 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 121815648 is about 11037.0126392969. The cubic root of 121815648 is about 495.7176245658.

The spelling of 121815648 in words is "one hundred twenty-one million, eight hundred fifteen thousand, six hundred forty-eight".