1645772889 has 8 divisors (see below), whose sum is σ = 2289771072. Its totient is φ = 1049478320.

The previous prime is 1645772879. The next prime is 1645772903. The reversal of 1645772889 is 9882775461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1645772889 - 2¹⁷ = 1645641817 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1645772819) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11925822 + ... + 11925959.

It is an arithmetic number, because the mean of its divisors is an integer number (286221384).

Almost surely, 2^1645772889 is an apocalyptic number.

It is an amenable number.

1645772889 is a deficient number, since it is larger than the sum of its proper divisors (643998183).

1645772889 is a wasteful number, since it uses less digits than its factorization.

1645772889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23851807.

The product of its digits is 6773760, while the sum is 57.

The square root of 1645772889 is about 40568.1265157759. The cubic root of 1645772889 is about 1180.6557900755.

The spelling of 1645772889 in words is "one billion, six hundred forty-five million, seven hundred seventy-two thousand, eight hundred eighty-nine".