211931920 has 40 divisors (see below), whose sum is σ = 495622296. Its totient is φ = 84277248.

The previous prime is 211931899. The next prime is 211931927. The reversal of 211931920 is 29139112.

It can be written as a sum of positive squares in 4 ways, for example, as 6411024 + 205520896 = 2532^2 + 14336^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (211931927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6184 + ... + 21496.

Almost surely, 2^211931920 is an apocalyptic number.

211931920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 211931920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (247811148).

211931920 is an abundant number, since it is smaller than the sum of its proper divisors (283690376).

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

211931920 is a wasteful number, since it uses less digits than its factorization.

211931920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15499 (or 15493 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 211931920 is about 14557.8817140407. The cubic root of 211931920 is about 596.2093614578.

The spelling of 211931920 in words is "two hundred eleven million, nine hundred thirty-one thousand, nine hundred twenty".