221565061 has 4 divisors (see below), whose sum is σ = 233226400. Its totient is φ = 209903724.

The previous prime is 221565041. The next prime is 221565067. The reversal of 221565061 is 160565122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221565061 - 2⁷ = 221564933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221565067) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5830641 + ... + 5830678.

It is an arithmetic number, because the mean of its divisors is an integer number (58306600).

Almost surely, 2^221565061 is an apocalyptic number.

It is an amenable number.

221565061 is a deficient number, since it is larger than the sum of its proper divisors (11661339).

221565061 is a wasteful number, since it uses less digits than its factorization.

221565061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11661338.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 221565061 is about 14885.0616726972. The cubic root of 221565061 is about 605.1092041562.

It can be divided in two parts, 2215 and 65061, that added together give a palindrome (67276).

The spelling of 221565061 in words is "two hundred twenty-one million, five hundred sixty-five thousand, sixty-one".