221421005 has 16 divisors (see below), whose sum is σ = 302977584. Its totient is φ = 153891840.

The previous prime is 221420959. The next prime is 221421017. The reversal of 221421005 is 500124122.

It can be written as a sum of positive squares in 8 ways, for example, as 38576521 + 182844484 = 6211^2 + 13522^2 .

It is a de Polignac number, because none of the positive numbers 2^k-221421005 is a prime.

It is a super-2 number, since 2×221421005² = 98054522910420050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

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, 99086 + ... + 101295.

It is an arithmetic number, because the mean of its divisors is an integer number (18936099).

Almost surely, 2^221421005 is an apocalyptic number.

It is an amenable number.

221421005 is a deficient number, since it is larger than the sum of its proper divisors (81556579).

221421005 is a wasteful number, since it uses less digits than its factorization.

221421005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200416.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 221421005 is about 14880.2219405491. The cubic root of 221421005 is about 604.9780334897.

Adding to 221421005 its reverse (500124122), we get a palindrome (721545127).

The spelling of 221421005 in words is "two hundred twenty-one million, four hundred twenty-one thousand, five".