221538000 has 80 divisors (see below), whose sum is σ = 714257856. Its totient is φ = 59075200.

The previous prime is 221537971. The next prime is 221538011. The reversal of 221538000 is 835122.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 12462 + ... + 24461.

Almost surely, 2^221538000 is an apocalyptic number.

221538000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221538000 is an abundant number, since it is smaller than the sum of its proper divisors (492719856).

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

221538000 is a wasteful number, since it uses less digits than its factorization.

221538000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36949 (or 36933 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 221538000 is about 14884.1526463551. The cubic root of 221538000 is about 605.0845680113.

The spelling of 221538000 in words is "two hundred twenty-one million, five hundred thirty-eight thousand".