1890091009 has 4 divisors (see below), whose sum is σ = 1902608320. Its totient is φ = 1877573700.

The previous prime is 1890090977. The next prime is 1890091057. The reversal of 1890091009 is 9001900981.

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: 9001900981 = 21179 ⋅425039.

It is a cyclic number.

It is not a de Polignac number, because 1890091009 - 2⁵ = 1890090977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1890091069) 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, 6258429 + ... + 6258730.

It is an arithmetic number, because the mean of its divisors is an integer number (475652080).

Almost surely, 2^1890091009 is an apocalyptic number.

It is an amenable number.

1890091009 is a deficient number, since it is larger than the sum of its proper divisors (12517311).

1890091009 is a wasteful number, since it uses less digits than its factorization.

1890091009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12517310.

The product of its (nonzero) digits is 5832, while the sum is 37.

The square root of 1890091009 is about 43475.1769289097. The cubic root of 1890091009 is about 1236.4054348121.

The spelling of 1890091009 in words is "one billion, eight hundred ninety million, ninety-one thousand, nine".