1825621821 has 48 divisors (see below), whose sum is σ = 2894528000. Its totient is φ = 1146652848.

The previous prime is 1825621813. The next prime is 1825621841. The reversal of 1825621821 is 1281265281.

1825621821 is a `hidden beast` number, since 1 + 8 + 2 + 5 + 621 + 8 + 21 = 666.

It is not a de Polignac number, because 1825621821 - 2³ = 1825621813 is a prime.

It is a super-2 number, since 2×1825621821² = 6665790066622712082, 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 (1825621841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 917790 + ... + 919776.

Almost surely, 2^1825621821 is an apocalyptic number.

It is an amenable number.

1825621821 is a deficient number, since it is larger than the sum of its proper divisors (1068906179).

1825621821 is a wasteful number, since it uses less digits than its factorization.

1825621821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2220 (or 2208 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 1825621821 is about 42727.2959710768. The cubic root of 1825621821 is about 1222.1849720845.

The spelling of 1825621821 in words is "one billion, eight hundred twenty-five million, six hundred twenty-one thousand, eight hundred twenty-one".