221420736 has 112 divisors (see below), whose sum is σ = 658144480. Its totient is φ = 72990720.

The previous prime is 221420681. The next prime is 221420741. The reversal of 221420736 is 637024122.

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 166956 + ... + 168276.

It is an arithmetic number, because the mean of its divisors is an integer number (5876290).

Almost surely, 2^221420736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221420736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (329072240).

221420736 is an abundant number, since it is smaller than the sum of its proper divisors (436723744).

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

221420736 is a wasteful number, since it uses less digits than its factorization.

221420736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1439 (or 1423 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 221420736 is about 14880.2129017027. The cubic root of 221420736 is about 604.9777884977.

Adding to 221420736 its reverse (637024122), we get a palindrome (858444858).

The spelling of 221420736 in words is "two hundred twenty-one million, four hundred twenty thousand, seven hundred thirty-six".