211995820 has 24 divisors (see below), whose sum is σ = 446140800. Its totient is φ = 84617472.

The previous prime is 211995811. The next prime is 211995821. The reversal of 211995820 is 28599112.

It is a self number, because there is not a number n which added to its sum of digits gives 211995820.

It is not an unprimeable number, because it can be changed into a prime (211995821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1485 + ... + 20644.

It is an arithmetic number, because the mean of its divisors is an integer number (18589200).

Almost surely, 2^211995820 is an apocalyptic number.

211995820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

211995820 is an abundant number, since it is smaller than the sum of its proper divisors (234144980).

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

211995820 is a wasteful number, since it uses less digits than its factorization.

211995820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22617 (or 22615 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 211995820 is about 14560.0762360642. The cubic root of 211995820 is about 596.2692768462.

The spelling of 211995820 in words is "two hundred eleven million, nine hundred ninety-five thousand, eight hundred twenty".