121601610 has 144 divisors (see below), whose sum is σ = 356409144. Its totient is φ = 28574208.

The previous prime is 121601593. The next prime is 121601651. The reversal of 121601610 is 16106121.

121601610 is a `hidden beast` number, since 1 + 2 + 1 + 601 + 61 + 0 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 36832761 + 84768849 = 6069^2 + 9207^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2294344 + ... + 2294396.

Almost surely, 2^121601610 is an apocalyptic number.

121601610 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 121601610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (178204572).

121601610 is an abundant number, since it is smaller than the sum of its proper divisors (234807534).

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

121601610 is a wasteful number, since it uses less digits than its factorization.

121601610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 121601610 is about 11027.3120024782. The cubic root of 121601610 is about 495.4271183395.

Adding to 121601610 its reverse (16106121), we get a palindrome (137707731).

The spelling of 121601610 in words is "one hundred twenty-one million, six hundred one thousand, six hundred ten".