3121800 has 144 divisors (see below), whose sum is σ = 10884720. Its totient is φ = 739200.

The previous prime is 3121771. The next prime is 3121817. The reversal of 3121800 is 81213.

3121800 = T₂₀₀ + T₂₀₁ + ... + T₂₉₈.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 3121800.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 72579 + ... + 72621.

Almost surely, 2^3121800 is an apocalyptic number.

3121800 is a gapful number since it is divisible by the number (30) 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 3121800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5442360).

3121800 is an abundant number, since it is smaller than the sum of its proper divisors (7762920).

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

3121800 is a wasteful number, since it uses less digits than its factorization.

3121800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 3121800 is about 1766.8616244630. The cubic root of 3121800 is about 146.1509666312.

It can be divided in two parts, 312 and 1800, that added together give a palindrome (2112).

The spelling of 3121800 in words is "three million, one hundred twenty-one thousand, eight hundred".