1721441605 has 12 divisors (see below), whose sum is σ = 2236856580. Its totient is φ = 1271217792.

The previous prime is 1721441567. The next prime is 1721441609. The reversal of 1721441605 is 5061441271.

It can be written as a sum of positive squares in 6 ways, for example, as 657768609 + 1063672996 = 25647^2 + 32614^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1721441605 is a prime.

It is a super-2 number, since 2×1721441605² = 5926722398849952050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721441609) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1017760 + ... + 1019449.

It is an arithmetic number, because the mean of its divisors is an integer number (186404715).

Almost surely, 2^1721441605 is an apocalyptic number.

It is an amenable number.

1721441605 is a deficient number, since it is larger than the sum of its proper divisors (515414975).

1721441605 is a wasteful number, since it uses less digits than its factorization.

1721441605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2037240 (or 2037227 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 1721441605 is about 41490.2591580241. The cubic root of 1721441605 is about 1198.4799283073.

Adding to 1721441605 its reverse (5061441271), we get a palindrome (6782882876).

The spelling of 1721441605 in words is "one billion, seven hundred twenty-one million, four hundred forty-one thousand, six hundred five".