121681920 has 192 divisors, whose sum is σ = 413955360. Its totient is φ = 30408704.

The previous prime is 121681907. The next prime is 121681921. The reversal of 121681920 is 29186121.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121681921) 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, 522124 + ... + 522356.

Almost surely, 2^121681920 is an apocalyptic number.

121681920 is a gapful number since it is divisible by the number (10) 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 121681920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (206977680).

121681920 is an abundant number, since it is smaller than the sum of its proper divisors (292273440).

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

121681920 is a wasteful number, since it uses less digits than its factorization.

121681920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280 (or 260 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 30.

The square root of 121681920 is about 11030.9528146938. The cubic root of 121681920 is about 495.5361601962.

The spelling of 121681920 in words is "one hundred twenty-one million, six hundred eighty-one thousand, nine hundred twenty".