221621036 has 48 divisors (see below), whose sum is σ = 482771520. Its totient is φ = 86676480.

The previous prime is 221621021. The next prime is 221621063. The reversal of 221621036 is 630126122.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28976 + ... + 35816.

It is an arithmetic number, because the mean of its divisors is an integer number (10057740).

Almost surely, 2^221621036 is an apocalyptic number.

221621036 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221621036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (241385760).

221621036 is an abundant number, since it is smaller than the sum of its proper divisors (261150484).

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

221621036 is a wasteful number, since it uses less digits than its factorization.

221621036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6954 (or 6952 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 221621036 is about 14886.9417947408. The cubic root of 221621036 is about 605.1601570390.

Adding to 221621036 its reverse (630126122), we get a palindrome (851747158).

The spelling of 221621036 in words is "two hundred twenty-one million, six hundred twenty-one thousand, thirty-six".