1890989865 has 12 divisors (see below), whose sum is σ = 3277715844. Its totient is φ = 1008527904.

The previous prime is 1890989861. The next prime is 1890989911. The reversal of 1890989865 is 5689890981.

1890989865 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 528494121 + 1362495744 = 22989^2 + 36912^2 .

It is not a de Polignac number, because 1890989865 - 2² = 1890989861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1890989861) 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, 21010954 + ... + 21011043.

It is an arithmetic number, because the mean of its divisors is an integer number (273142987).

Almost surely, 2^1890989865 is an apocalyptic number.

1890989865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1890989865 is a deficient number, since it is larger than the sum of its proper divisors (1386725979).

1890989865 is a wasteful number, since it uses less digits than its factorization.

1890989865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42022008 (or 42022005 counting only the distinct ones).

The product of its (nonzero) digits is 11197440, while the sum is 63.

The square root of 1890989865 is about 43485.5132774123. The cubic root of 1890989865 is about 1236.6013996823.

The spelling of 1890989865 in words is "one billion, eight hundred ninety million, nine hundred eighty-nine thousand, eight hundred sixty-five".