121905810 has 192 divisors, whose sum is σ = 376451712. Its totient is φ = 28118016.

The previous prime is 121905803. The next prime is 121905829. The reversal of 121905810 is 18509121.

It is a super-2 number, since 2×121905810² = 29722053023512200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 536917 + ... + 537143.

It is an arithmetic number, because the mean of its divisors is an integer number (1960686).

Almost surely, 2^121905810 is an apocalyptic number.

121905810 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 121905810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (188225856).

121905810 is an abundant number, since it is smaller than the sum of its proper divisors (254545902).

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

121905810 is a wasteful number, since it uses less digits than its factorization.

121905810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 267 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 121905810 is about 11041.0964129474. The cubic root of 121905810 is about 495.8398964051.

The spelling of 121905810 in words is "one hundred twenty-one million, nine hundred five thousand, eight hundred ten".