400211820 has 144 divisors (see below), whose sum is σ = 1314724320. Its totient is φ = 101056896.

The previous prime is 400211813. The next prime is 400211821. The reversal of 400211820 is 28112004.

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

It is a junction number, because it is equal to n+sod(n) for n = 400211793 and 400211802.

It is not an unprimeable number, because it can be changed into a prime (400211821) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 193914 + ... + 195966.

It is an arithmetic number, because the mean of its divisors is an integer number (9130030).

Almost surely, 2^400211820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400211820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (657362160).

400211820 is an abundant number, since it is smaller than the sum of its proper divisors (914512500).

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

400211820 is a wasteful number, since it uses less digits than its factorization.

400211820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109 (or 2082 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 400211820 is about 20005.2947991276. The cubic root of 400211820 is about 736.9363353693.

Adding to 400211820 its reverse (28112004), we get a palindrome (428323824).

The spelling of 400211820 in words is "four hundred million, two hundred eleven thousand, eight hundred twenty".