It is a plaindrome in base 10.
It is a congruent number.
It is an unprimeable number.
21245678 is an apocalyptic number.
It is a practical number, because each smaller number is the sum of distinct divisors of 1245678, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1532160).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1245678 is a wasteful number, since it uses less digits than its factorization.
1245678 is an evil number, because the sum of its binary digits is even.
The square root of 1245678 is about 1116.0994579337. The cubic root of 1245678 is about 107.5974382460.
The spelling of 1245678 in words is "one million, two hundred forty-five thousand, six hundred seventy-eight".