2145251221 has 8 divisors (see below), whose sum is σ = 2306206080. Its totient is φ = 1989101088.

The previous prime is 2145251081. The next prime is 2145251237. The reversal of 2145251221 is 1221525412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2145251221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2145251281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1200256 + ... + 1202041.

It is an arithmetic number, because the mean of its divisors is an integer number (288275760).

Almost surely, 2^2145251221 is an apocalyptic number.

It is an amenable number.

2145251221 is a deficient number, since it is larger than the sum of its proper divisors (160954859).

2145251221 is a wasteful number, since it uses less digits than its factorization.

2145251221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2402363.

The product of its digits is 1600, while the sum is 25.

The square root of 2145251221 is about 46316.8567694311. The cubic root of 2145251221 is about 1289.7119363597.

Adding to 2145251221 its reverse (1221525412), we get a palindrome (3366776633).

The spelling of 2145251221 in words is "two billion, one hundred forty-five million, two hundred fifty-one thousand, two hundred twenty-one".