1821261229 has 4 divisors (see below), whose sum is σ = 1827193984. Its totient is φ = 1815328476.

The previous prime is 1821261227. The next prime is 1821261241. The reversal of 1821261229 is 9221621281.

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 1821261229 - 2¹ = 1821261227 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1821261194 and 1821261203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821261223) 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, 2965917 + ... + 2966530.

It is an arithmetic number, because the mean of its divisors is an integer number (456798496).

Almost surely, 2^1821261229 is an apocalyptic number.

It is an amenable number.

1821261229 is a deficient number, since it is larger than the sum of its proper divisors (5932755).

1821261229 is an equidigital number, since it uses as much as digits as its factorization.

1821261229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5932754.

The product of its digits is 6912, while the sum is 34.

The square root of 1821261229 is about 42676.2372872773. The cubic root of 1821261229 is about 1221.2111123266.

The spelling of 1821261229 in words is "one billion, eight hundred twenty-one million, two hundred sixty-one thousand, two hundred twenty-nine".