1821084901 has 4 divisors (see below), whose sum is σ = 1821470112. Its totient is φ = 1820699692.

The previous prime is 1821084883. The next prime is 1821084917. The reversal of 1821084901 is 1094801281.

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 an emirpimes, since its reverse is a distinct semiprime: 1094801281 = 7 ⋅156400183.

It is a cyclic number.

It is not a de Polignac number, because 1821084901 - 2¹¹ = 1821082853 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 (1821081901) 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, 185425 + ... + 194998.

It is an arithmetic number, because the mean of its divisors is an integer number (455367528).

Almost surely, 2^1821084901 is an apocalyptic number.

It is an amenable number.

1821084901 is a deficient number, since it is larger than the sum of its proper divisors (385211).

1821084901 is an equidigital number, since it uses as much as digits as its factorization.

1821084901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385210.

The product of its (nonzero) digits is 4608, while the sum is 34.

The square root of 1821084901 is about 42674.1713569227. The cubic root of 1821084901 is about 1221.1716999569.

The spelling of 1821084901 in words is "one billion, eight hundred twenty-one million, eighty-four thousand, nine hundred one".