The square root of 2640625 is 1625.
It is an Ulam number.
It is a Duffinian number.
It is a self number, because there is not a number n which added to its sum of digits gives 2640625.
It is an unprimeable number.
22640625 is an apocalyptic number.
2640625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.
2640625 is the 1625-th square number.
2640625 is the 813-rd centered octagonal number.
It is an amenable number.
2640625 is an frugal number, since it uses more digits than its factorization.
2640625 is an evil number, because the sum of its binary digits is even.
The cubic root of 2640625 is about 138.2193703420.
Multiplying 2640625 by its sum of digits (25), we get a square (66015625 = 81252).
2640625 divided by its sum of digits (25) gives a square (105625 = 3252).
The spelling of 2640625 in words is "two million, six hundred forty thousand, six hundred twenty-five".