400201820 has 24 divisors (see below), whose sum is σ = 860923728. Its totient is φ = 156176000.

The previous prime is 400201819. The next prime is 400201829. The reversal of 400201820 is 28102004.

It is a super-2 number, since 2×400201820² = 320322993462624800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400201829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243206 + ... + 244845.

It is an arithmetic number, because the mean of its divisors is an integer number (35871822).

Almost surely, 2^400201820 is an apocalyptic number.

It is an amenable number.

400201820 is an abundant number, since it is smaller than the sum of its proper divisors (460721908).

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

400201820 is a wasteful number, since it uses less digits than its factorization.

400201820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488101 (or 488099 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 400201820 is about 20005.0448637337. The cubic root of 400201820 is about 736.9301974324.

Adding to 400201820 its reverse (28102004), we get a palindrome (428303824).

The spelling of 400201820 in words is "four hundred million, two hundred one thousand, eight hundred twenty".