121565664 has 96 divisors (see below), whose sum is σ = 386830080. Its totient is φ = 36835200.

The previous prime is 121565627. The next prime is 121565669. The reversal of 121565664 is 466565121.

It is a tau number, because it is divible by the number of its divisors (96).

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 (121565669) 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, 3109 + ... + 15899.

It is an arithmetic number, because the mean of its divisors is an integer number (4029480).

Almost surely, 2^121565664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121565664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (193415040).

121565664 is an abundant number, since it is smaller than the sum of its proper divisors (265264416).

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

121565664 is a wasteful number, since it uses less digits than its factorization.

121565664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12821 (or 12807 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 121565664 is about 11025.6820197210. The cubic root of 121565664 is about 495.3782966771.

The spelling of 121565664 in words is "one hundred twenty-one million, five hundred sixty-five thousand, six hundred sixty-four".