2237981821 has 4 divisors (see below), whose sum is σ = 2238084000. Its totient is φ = 2237879644.

The previous prime is 2237981819. The next prime is 2237981831. The reversal of 2237981821 is 1281897322.

2237981821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2237981821 - 2¹ = 2237981819 is a prime.

It is a super-2 number, since 2×2237981821² = 10017125262252952082, 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 (2237981831) 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, 3391 + ... + 66988.

It is an arithmetic number, because the mean of its divisors is an integer number (559521000).

Almost surely, 2^2237981821 is an apocalyptic number.

It is an amenable number.

2237981821 is a deficient number, since it is larger than the sum of its proper divisors (102179).

2237981821 is an equidigital number, since it uses as much as digits as its factorization.

2237981821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102178.

The product of its digits is 96768, while the sum is 43.

The square root of 2237981821 is about 47307.3125531350. The cubic root of 2237981821 is about 1308.0334537809.

The spelling of 2237981821 in words is "two billion, two hundred thirty-seven million, nine hundred eighty-one thousand, eight hundred twenty-one".