121979520 has 320 divisors, whose sum is σ = 471711240. Its totient is φ = 29859840.

The previous prime is 121979497. The next prime is 121979581. The reversal of 121979520 is 25979121.

121979520 is a `hidden beast` number, since 121 + 9 + 7 + 9 + 520 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 35712576 + 86266944 = 5976^2 + 9288^2 .

It is a tau number, because it is divible by the number of its divisors (320).

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

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 673830 + ... + 674010.

Almost surely, 2^121979520 is an apocalyptic number.

121979520 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 121979520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (235855620).

121979520 is an abundant number, since it is smaller than the sum of its proper divisors (349731720).

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

121979520 is a wasteful number, since it uses less digits than its factorization.

121979520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 11340, while the sum is 36.

The square root of 121979520 is about 11044.4338922373. The cubic root of 121979520 is about 495.9398123291.

The spelling of 121979520 in words is "one hundred twenty-one million, nine hundred seventy-nine thousand, five hundred twenty".