121781280 has 96 divisors (see below), whose sum is σ = 390930624. Its totient is φ = 31855616.

The previous prime is 121781273. The next prime is 121781287. The reversal of 121781280 is 82187121.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (121781273) and next prime (121781287).

It is a tau number, because it is divible by the number of its divisors (96).

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

It is not an unprimeable number, because it can be changed into a prime (121781287) 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, 23047 + ... + 27833.

It is an arithmetic number, because the mean of its divisors is an integer number (4072194).

Almost surely, 2^121781280 is an apocalyptic number.

121781280 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 121781280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (195465312).

121781280 is an abundant number, since it is smaller than the sum of its proper divisors (269149344).

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

121781280 is a wasteful number, since it uses less digits than its factorization.

121781280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4858 (or 4850 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 30.

The square root of 121781280 is about 11035.4555864269. The cubic root of 121781280 is about 495.6710010379.

The spelling of 121781280 in words is "one hundred twenty-one million, seven hundred eighty-one thousand, two hundred eighty".