2145020221 has 4 divisors (see below), whose sum is σ = 2161910272. Its totient is φ = 2128130172.

The previous prime is 2145020191. The next prime is 2145020243. The reversal of 2145020221 is 1220205412.

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 2145020221 - 2⁷ = 2145020093 is a prime.

It is a super-2 number, since 2×2145020221² = 9202223496997777682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2145020261) 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, 8444835 + ... + 8445088.

It is an arithmetic number, because the mean of its divisors is an integer number (540477568).

Almost surely, 2^2145020221 is an apocalyptic number.

It is an amenable number.

2145020221 is a deficient number, since it is larger than the sum of its proper divisors (16890051).

2145020221 is a wasteful number, since it uses less digits than its factorization.

2145020221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16890050.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 2145020221 is about 46314.3630097619. The cubic root of 2145020221 is about 1289.6656427682.

Adding to 2145020221 its reverse (1220205412), we get a palindrome (3365225633).

The spelling of 2145020221 in words is "two billion, one hundred forty-five million, twenty thousand, two hundred twenty-one".