2151830221 has 4 divisors (see below), whose sum is σ = 2152745532. Its totient is φ = 2150914912.

The previous prime is 2151830207. The next prime is 2151830269. The reversal of 2151830221 is 1220381512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 289476196 + 1862354025 = 17014^2 + 43155^2 .

It is a cyclic number.

It is not a de Polignac number, because 2151830221 - 2²³ = 2143441613 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 (2151830321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454120 + ... + 458833.

It is an arithmetic number, because the mean of its divisors is an integer number (538186383).

Almost surely, 2^2151830221 is an apocalyptic number.

It is an amenable number.

2151830221 is a deficient number, since it is larger than the sum of its proper divisors (915311).

2151830221 is an equidigital number, since it uses as much as digits as its factorization.

2151830221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915310.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 2151830221 is about 46387.8240597681. The cubic root of 2151830221 is about 1291.0290090987.

The spelling of 2151830221 in words is "two billion, one hundred fifty-one million, eight hundred thirty thousand, two hundred twenty-one".