121781550 has 96 divisors (see below), whose sum is σ = 343906560. Its totient is φ = 28230400.

The previous prime is 121781537. The next prime is 121781563. The reversal of 121781550 is 55187121.

It is an interprime number because it is at equal distance from previous prime (121781537) and next prime (121781563).

It is a super-3 number, since 3×121781550³ (a number of 25 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 36346 + ... + 39554.

It is an arithmetic number, because the mean of its divisors is an integer number (3582360).

Almost surely, 2^121781550 is an apocalyptic number.

121781550 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 121781550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171953280).

121781550 is an abundant number, since it is smaller than the sum of its proper divisors (222125010).

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

121781550 is a wasteful number, since it uses less digits than its factorization.

121781550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3258 (or 3253 counting only the distinct ones).

The product of its (nonzero) digits is 2800, while the sum is 30.

The square root of 121781550 is about 11035.4678197166. The cubic root of 121781550 is about 495.6713673533.

The spelling of 121781550 in words is "one hundred twenty-one million, seven hundred eighty-one thousand, five hundred fifty".