221013765 has 160 divisors (see below), whose sum is σ = 485548800. Its totient is φ = 96018048.

The previous prime is 221013761. The next prime is 221013769. The reversal of 221013765 is 567310122.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (221013761) and next prime (221013769).

It is not a de Polignac number, because 221013765 - 2² = 221013761 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221013761) by changing a digit.

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 159 ways as a sum of consecutive naturals, for example, 5139834 + ... + 5139876.

It is an arithmetic number, because the mean of its divisors is an integer number (3034680).

Almost surely, 2^221013765 is an apocalyptic number.

It is an amenable number.

221013765 is an abundant number, since it is smaller than the sum of its proper divisors (264535035).

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

221013765 is an equidigital number, since it uses as much as digits as its factorization.

221013765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 221013765 is about 14866.5317071602. The cubic root of 221013765 is about 604.6069117409.

Adding to 221013765 its reverse (567310122), we get a palindrome (788323887).

The spelling of 221013765 in words is "two hundred twenty-one million, thirteen thousand, seven hundred sixty-five".