2120405400 has 72 divisors (see below), whose sum is σ = 7121034180. Its totient is φ = 565440960.

The previous prime is 2120405389. The next prime is 2120405401. The reversal of 2120405400 is 45040212.

2120405400 is a `hidden beast` number, since 2 + 120 + 4 + 0 + 540 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×2120405400² = 8992238120698320000, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2120405401) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 587202 + ... + 590801.

Almost surely, 2^2120405400 is an apocalyptic number.

2120405400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2120405400 is an abundant number, since it is smaller than the sum of its proper divisors (5000628780).

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

2120405400 is a wasteful number, since it uses less digits than its factorization.

2120405400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1178025 (or 1178013 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 2120405400 is about 46047.8598851239. The cubic root of 2120405400 is about 1284.7135376624.

Adding to 2120405400 its reverse (45040212), we get a palindrome (2165445612).

The spelling of 2120405400 in words is "two billion, one hundred twenty million, four hundred five thousand, four hundred".