211222820 has 24 divisors (see below), whose sum is σ = 445216128. Its totient is φ = 84175200.

The previous prime is 211222811. The next prime is 211222831. The reversal of 211222820 is 28222112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 211222792 and 211222801.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14066 + ... + 24905.

It is an arithmetic number, because the mean of its divisors is an integer number (18550672).

Almost surely, 2^211222820 is an apocalyptic number.

211222820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

211222820 is an abundant number, since it is smaller than the sum of its proper divisors (233993308).

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

211222820 is a wasteful number, since it uses less digits than its factorization.

211222820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39251 (or 39249 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 211222820 is about 14533.5068032461. The cubic root of 211222820 is about 595.5436689840.

Adding to 211222820 its reverse (28222112), we get a palindrome (239444932).

The spelling of 211222820 in words is "two hundred eleven million, two hundred twenty-two thousand, eight hundred twenty".