121921840 has 20 divisors (see below), whose sum is σ = 283468464. Its totient is φ = 48768704.

The previous prime is 121921837. The next prime is 121921867. The reversal of 121921840 is 48129121.

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 121921799 and 121921808.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 761932 + ... + 762091.

Almost surely, 2^121921840 is an apocalyptic number.

121921840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121921840 is an abundant number, since it is smaller than the sum of its proper divisors (161546624).

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

121921840 is a wasteful number, since it uses less digits than its factorization.

121921840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1524036 (or 1524030 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 121921840 is about 11041.8223133684. The cubic root of 121921840 is about 495.8616289355.

The spelling of 121921840 in words is "one hundred twenty-one million, nine hundred twenty-one thousand, eight hundred forty".