221400870 has 32 divisors (see below), whose sum is σ = 532604160. Its totient is φ = 58902240.

The previous prime is 221400847. The next prime is 221400871. The reversal of 221400870 is 78004122.

221400870 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 221400870.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221400871) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4765 + ... + 21575.

It is an arithmetic number, because the mean of its divisors is an integer number (16643880).

Almost surely, 2^221400870 is an apocalyptic number.

221400870 is an abundant number, since it is smaller than the sum of its proper divisors (311203290).

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

221400870 is a wasteful number, since it uses less digits than its factorization.

221400870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17260.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 221400870 is about 14879.5453559576. The cubic root of 221400870 is about 604.9596949677.

Adding to 221400870 its reverse (78004122), we get a palindrome (299404992).

The spelling of 221400870 in words is "two hundred twenty-one million, four hundred thousand, eight hundred seventy".