213123456 has 384 divisors, whose sum is σ = 801964800. Its totient is φ = 52752384.

The previous prime is 213123439. The next prime is 213123457. The reversal of 213123456 is 654321312.

213123456 is a `hidden beast` number, since 2 + 1 + 312 + 345 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213123457) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1991755 + ... + 1991861.

It is an arithmetic number, because the mean of its divisors is an integer number (2088450).

Almost surely, 2^213123456 is an apocalyptic number.

213123456 is a gapful number since it is divisible by the number (26) 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 213123456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (400982400).

213123456 is an abundant number, since it is smaller than the sum of its proper divisors (588841344).

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

213123456 is a wasteful number, since it uses less digits than its factorization.

213123456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 151 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 213123456 is about 14598.7484395067. The cubic root of 213123456 is about 597.3246216487.

Adding to 213123456 its reverse (654321312), we get a palindrome (867444768).

The spelling of 213123456 in words is "two hundred thirteen million, one hundred twenty-three thousand, four hundred fifty-six".