121638645 has 32 divisors (see below), whose sum is σ = 216873600. Its totient is φ = 64685952.

The previous prime is 121638641. The next prime is 121638667. The reversal of 121638645 is 546836121.

It is a happy number.

121638645 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 3 + 8 + 645 = 666.

It is not a de Polignac number, because 121638645 - 2² = 121638641 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121638641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54114 + ... + 56316.

It is an arithmetic number, because the mean of its divisors is an integer number (6777300).

Almost surely, 2^121638645 is an apocalyptic number.

121638645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121638645 is a deficient number, since it is larger than the sum of its proper divisors (95234955).

121638645 is a wasteful number, since it uses less digits than its factorization.

121638645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2626 (or 2620 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 121638645 is about 11028.9911143314. The cubic root of 121638645 is about 495.4774090140.

The spelling of 121638645 in words is "one hundred twenty-one million, six hundred thirty-eight thousand, six hundred forty-five".