221555340 has 36 divisors (see below), whose sum is σ = 672051744. Its totient is φ = 59081376.

The previous prime is 221555311. The next prime is 221555351. The reversal of 221555340 is 43555122.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 615252 + ... + 615611.

It is an arithmetic number, because the mean of its divisors is an integer number (18668104).

Almost surely, 2^221555340 is an apocalyptic number.

221555340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221555340 is an abundant number, since it is smaller than the sum of its proper divisors (450496404).

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

221555340 is a wasteful number, since it uses less digits than its factorization.

221555340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1230878 (or 1230873 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

The square root of 221555340 is about 14884.7351336865. The cubic root of 221555340 is about 605.1003544567.

It can be divided in two parts, 22155 and 5340, that added together give a triangular number (27495 = T₂₃₄).

The spelling of 221555340 in words is "two hundred twenty-one million, five hundred fifty-five thousand, three hundred forty".