1645778505 has 16 divisors (see below), whose sum is σ = 3009423744. Its totient is φ = 752355840.

The previous prime is 1645778489. The next prime is 1645778513. The reversal of 1645778505 is 5058775461.

It is not a de Polignac number, because 1645778505 - 2⁴ = 1645778489 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7836936 + ... + 7837145.

It is an arithmetic number, because the mean of its divisors is an integer number (188088984).

Almost surely, 2^1645778505 is an apocalyptic number.

1645778505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1645778505 is a deficient number, since it is larger than the sum of its proper divisors (1363645239).

1645778505 is a wasteful number, since it uses less digits than its factorization.

1645778505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15674096.

The product of its (nonzero) digits is 1176000, while the sum is 48.

The square root of 1645778505 is about 40568.1957326179. The cubic root of 1645778505 is about 1180.6571330221.

The spelling of 1645778505 in words is "one billion, six hundred forty-five million, seven hundred seventy-eight thousand, five hundred five".