220406640 has 40 divisors (see below), whose sum is σ = 683261328. Its totient is φ = 58775040.

The previous prime is 220406639. The next prime is 220406651. The reversal of 220406640 is 46604022.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 220406640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 458941 + ... + 459420.

Almost surely, 2^220406640 is an apocalyptic number.

220406640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

220406640 is an abundant number, since it is smaller than the sum of its proper divisors (462854688).

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

220406640 is a wasteful number, since it uses less digits than its factorization.

220406640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 918377 (or 918371 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 220406640 is about 14846.0984773778. The cubic root of 220406640 is about 604.0527854691.

It can be divided in two parts, 22040 and 6640, that added together give a triangular number (28680 = T₂₃₉).

The spelling of 220406640 in words is "two hundred twenty million, four hundred six thousand, six hundred forty".