2130020821 has 4 divisors (see below), whose sum is σ = 2242127200. Its totient is φ = 2017914444.

The previous prime is 2130020813. The next prime is 2130020833. The reversal of 2130020821 is 1280200312.

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 2130020821 - 2³ = 2130020813 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 112106359 = 2130020821 / (2 + 1 + 3 + 0 + 0 + 2 + 0 + 8 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2130023821) 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, 56053161 + ... + 56053198.

It is an arithmetic number, because the mean of its divisors is an integer number (560531800).

Almost surely, 2^2130020821 is an apocalyptic number.

It is an amenable number.

2130020821 is a deficient number, since it is larger than the sum of its proper divisors (112106379).

2130020821 is a wasteful number, since it uses less digits than its factorization.

2130020821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112106378.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 2130020821 is about 46152.1486065384. The cubic root of 2130020821 is about 1286.6525435896.

The spelling of 2130020821 in words is "two billion, one hundred thirty million, twenty thousand, eight hundred twenty-one".