1888890021 has 12 divisors (see below), whose sum is σ = 2756525772. Its totient is φ = 1246277376.

The previous prime is 1888890001. The next prime is 1888890053. The reversal of 1888890021 is 1200988881.

It can be written as a sum of positive squares in 2 ways, for example, as 471367521 + 1417522500 = 21711^2 + 37650^2 .

It is not a de Polignac number, because 1888890021 - 2¹⁰ = 1888888997 is a prime.

It is a super-2 number, since 2×1888890021² = 7135811022866760882, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1888890001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1080966 + ... + 1082711.

It is an arithmetic number, because the mean of its divisors is an integer number (229710481).

Almost surely, 2^1888890021 is an apocalyptic number.

It is an amenable number.

1888890021 is a deficient number, since it is larger than the sum of its proper divisors (867635751).

1888890021 is a wasteful number, since it uses less digits than its factorization.

1888890021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2163780 (or 2163777 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 45.

The square root of 1888890021 is about 43461.3623923595. The cubic root of 1888890021 is about 1236.1435033840.

The spelling of 1888890021 in words is "one billion, eight hundred eighty-eight million, eight hundred ninety thousand, twenty-one".