121779840 has 512 divisors, whose sum is σ = 518192640. Its totient is φ = 23592960.

The previous prime is 121779817. The next prime is 121779859. The reversal of 121779840 is 48977121.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2970220 + ... + 2970260.

It is an arithmetic number, because the mean of its divisors is an integer number (1012095).

Almost surely, 2^121779840 is an apocalyptic number.

121779840 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 121779840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (259096320).

121779840 is an abundant number, since it is smaller than the sum of its proper divisors (396412800).

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

121779840 is a wasteful number, since it uses less digits than its factorization.

121779840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 39.

The square root of 121779840 is about 11035.3903419861. The cubic root of 121779840 is about 495.6690473467.

The spelling of 121779840 in words is "one hundred twenty-one million, seven hundred seventy-nine thousand, eight hundred forty".