121761640 has 128 divisors (see below), whose sum is σ = 367960320. Its totient is φ = 35020800.

The previous prime is 121761593. The next prime is 121761643. The reversal of 121761640 is 46167121.

121761640 = T₁₉₀₃ + T₁₉₀₄ + ... + T₁₉₆₇.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 121761599 and 121761608.

It is not an unprimeable number, because it can be changed into a prime (121761643) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38520 + ... + 41560.

It is an arithmetic number, because the mean of its divisors is an integer number (2874690).

Almost surely, 2^121761640 is an apocalyptic number.

121761640 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 121761640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183980160).

121761640 is an abundant number, since it is smaller than the sum of its proper divisors (246198680).

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

121761640 is a wasteful number, since it uses less digits than its factorization.

121761640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3083 (or 3079 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 121761640 is about 11034.5656914987. The cubic root of 121761640 is about 495.6443535328.

The spelling of 121761640 in words is "one hundred twenty-one million, seven hundred sixty-one thousand, six hundred forty".