1804858021 has 4 divisors (see below), whose sum is σ = 1806257344. Its totient is φ = 1803458700.

The previous prime is 1804857983. The next prime is 1804858031. The reversal of 1804858021 is 1208584081.

It is a happy number.

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: 1208584081 = 71 ⋅17022311.

It is a cyclic number.

It is not a de Polignac number, because 1804858021 - 2¹¹ = 1804855973 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 (1804858031) 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, 697725 + ... + 700306.

It is an arithmetic number, because the mean of its divisors is an integer number (451564336).

Almost surely, 2^1804858021 is an apocalyptic number.

It is an amenable number.

1804858021 is a deficient number, since it is larger than the sum of its proper divisors (1399323).

1804858021 is a wasteful number, since it uses less digits than its factorization.

1804858021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1399322.

The product of its (nonzero) digits is 20480, while the sum is 37.

The square root of 1804858021 is about 42483.6206201873. The cubic root of 1804858021 is about 1217.5337666301.

The spelling of 1804858021 in words is "one billion, eight hundred four million, eight hundred fifty-eight thousand, twenty-one".