2220401721 has 4 divisors (see below), whose sum is σ = 2960535632. Its totient is φ = 1480267812.

The previous prime is 2220401681. The next prime is 2220401737. The reversal of 2220401721 is 1271040222.

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 not a de Polignac number, because 2220401721 - 2⁷ = 2220401593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2220401021) 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, 370066951 + ... + 370066956.

It is an arithmetic number, because the mean of its divisors is an integer number (740133908).

Almost surely, 2^2220401721 is an apocalyptic number.

It is an amenable number.

2220401721 is a deficient number, since it is larger than the sum of its proper divisors (740133911).

2220401721 is an equidigital number, since it uses as much as digits as its factorization.

2220401721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740133910.

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 2220401721 is about 47121.1387914172. The cubic root of 2220401721 is about 1304.5994319684.

Adding to 2220401721 its reverse (1271040222), we get a palindrome (3491441943).

The spelling of 2220401721 in words is "two billion, two hundred twenty million, four hundred one thousand, seven hundred twenty-one".