1801728621 has 48 divisors (see below), whose sum is σ = 3385774080. Its totient is φ = 895260960.

The previous prime is 1801728619. The next prime is 1801728623. The reversal of 1801728621 is 1268271081.

1801728621 is a `hidden beast` number, since 1 + 8 + 0 + 1 + 7 + 28 + 621 = 666.

It is an interprime number because it is at equal distance from previous prime (1801728619) and next prime (1801728623).

It is not a de Polignac number, because 1801728621 - 2¹ = 1801728619 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1801728623) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 40581 + ... + 72458.

It is an arithmetic number, because the mean of its divisors is an integer number (70536960).

Almost surely, 2^1801728621 is an apocalyptic number.

1801728621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1801728621 is a deficient number, since it is larger than the sum of its proper divisors (1584045459).

1801728621 is a wasteful number, since it uses less digits than its factorization.

1801728621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113086 (or 113083 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 1801728621 is about 42446.7739763577. The cubic root of 1801728621 is about 1216.8296753465.

The spelling of 1801728621 in words is "one billion, eight hundred one million, seven hundred twenty-eight thousand, six hundred twenty-one".