211422640 has 80 divisors (see below), whose sum is σ = 577525536. Its totient is φ = 70963200.

The previous prime is 211422623. The next prime is 211422677. The reversal of 211422640 is 46224112.

It is a happy number.

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

It is a Harshad number since it is a multiple of its sum of digits (22).

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, 2200 + ... + 20680.

Almost surely, 2^211422640 is an apocalyptic number.

211422640 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 211422640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (288762768).

211422640 is an abundant number, since it is smaller than the sum of its proper divisors (366102896).

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

211422640 is a wasteful number, since it uses less digits than its factorization.

211422640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18518 (or 18512 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 211422640 is about 14540.3796374097. The cubic root of 211422640 is about 595.7314075846.

Adding to 211422640 its reverse (46224112), we get a palindrome (257646752).

The spelling of 211422640 in words is "two hundred eleven million, four hundred twenty-two thousand, six hundred forty".