121809786 has 48 divisors (see below), whose sum is σ = 284505696. Its totient is φ = 34666464.

The previous prime is 121809781. The next prime is 121809791. The reversal of 121809786 is 687908121.

It is an interprime number because it is at equal distance from previous prime (121809781) and next prime (121809791).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121809781) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 92545 + ... + 93851.

It is an arithmetic number, because the mean of its divisors is an integer number (5927202).

Almost surely, 2^121809786 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121809786, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142252848).

121809786 is an abundant number, since it is smaller than the sum of its proper divisors (162695910).

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

121809786 is a wasteful number, since it uses less digits than its factorization.

121809786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1643 (or 1636 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 42.

The square root of 121809786 is about 11036.7470751123. The cubic root of 121809786 is about 495.7096728142.

The spelling of 121809786 in words is "one hundred twenty-one million, eight hundred nine thousand, seven hundred eighty-six".