211215440 has 80 divisors (see below), whose sum is σ = 515966976. Its totient is φ = 80256000.

The previous prime is 211215413. The next prime is 211215451. The reversal of 211215440 is 44512112.

It is a happy number.

211215440 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×211215440² = 89223924188787200, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 351140 + ... + 351740.

Almost surely, 2^211215440 is an apocalyptic number.

211215440 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 211215440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257983488).

211215440 is an abundant number, since it is smaller than the sum of its proper divisors (304751536).

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

211215440 is a wasteful number, since it uses less digits than its factorization.

211215440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 828 (or 822 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 211215440 is about 14533.2529049762. The cubic root of 211215440 is about 595.5367329224.

Adding to 211215440 its reverse (44512112), we get a palindrome (255727552).

The spelling of 211215440 in words is "two hundred eleven million, two hundred fifteen thousand, four hundred forty".