221139870 has 64 divisors (see below), whose sum is σ = 611988480. Its totient is φ = 50093568.

The previous prime is 221139869. The next prime is 221139883. The reversal of 221139870 is 78931122.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19071 + ... + 28389.

It is an arithmetic number, because the mean of its divisors is an integer number (9562320).

Almost surely, 2^221139870 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221139870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (305994240).

221139870 is an abundant number, since it is smaller than the sum of its proper divisors (390848610).

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

221139870 is a wasteful number, since it uses less digits than its factorization.

221139870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9449.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 221139870 is about 14870.7723403998. The cubic root of 221139870 is about 604.7218811384.

The spelling of 221139870 in words is "two hundred twenty-one million, one hundred thirty-nine thousand, eight hundred seventy".