1721012213 has 4 divisors (see below), whose sum is σ = 1776528768. Its totient is φ = 1665495660.

The previous prime is 1721012203. The next prime is 1721012231. The reversal of 1721012213 is 3122101271.

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 1721012213 - 2⁶ = 1721012149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721012203) 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, 27758231 + ... + 27758292.

It is an arithmetic number, because the mean of its divisors is an integer number (444132192).

Almost surely, 2^1721012213 is an apocalyptic number.

It is an amenable number.

1721012213 is a deficient number, since it is larger than the sum of its proper divisors (55516555).

1721012213 is an equidigital number, since it uses as much as digits as its factorization.

1721012213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55516554.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 1721012213 is about 41485.0842231277. The cubic root of 1721012213 is about 1198.3802714294.

Adding to 1721012213 its reverse (3122101271), we get a palindrome (4843113484).

The spelling of 1721012213 in words is "one billion, seven hundred twenty-one million, twelve thousand, two hundred thirteen".