121393890 has 80 divisors (see below), whose sum is σ = 331047288. Its totient is φ = 31912704.

The previous prime is 121393847. The next prime is 121393949. The reversal of 121393890 is 98393121.

It can be written as a sum of positive squares in 4 ways, for example, as 101062809 + 20331081 = 10053^2 + 4509^2 .

It is a Curzon number.

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, 58104 + ... + 60156.

Almost surely, 2^121393890 is an apocalyptic number.

121393890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 121393890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165523644).

121393890 is an abundant number, since it is smaller than the sum of its proper divisors (209653398).

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

121393890 is a wasteful number, since it uses less digits than its factorization.

121393890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2145 (or 2136 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 121393890 is about 11017.8895438283. The cubic root of 121393890 is about 495.1448611837.

The spelling of 121393890 in words is "one hundred twenty-one million, three hundred ninety-three thousand, eight hundred ninety".