1645217287 has 12 divisors (see below), whose sum is σ = 1926023160. Its totient is φ = 1401197616.

The previous prime is 1645217267. The next prime is 1645217293. The reversal of 1645217287 is 7827125461.

It is a de Polignac number, because none of the positive numbers 2^k-1645217287 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645217207) 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, 99237 + ... + 114622.

It is an arithmetic number, because the mean of its divisors is an integer number (160501930).

Almost surely, 2^1645217287 is an apocalyptic number.

1645217287 is a deficient number, since it is larger than the sum of its proper divisors (280805873).

1645217287 is a wasteful number, since it uses less digits than its factorization.

1645217287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214030 (or 214023 counting only the distinct ones).

The product of its digits is 188160, while the sum is 43.

The square root of 1645217287 is about 40561.2781726612. The cubic root of 1645217287 is about 1180.5229146032.

It can be divided in two parts, 164521728 and 7, that multiplied together give a square (1151652096 = 33936²).

The spelling of 1645217287 in words is "one billion, six hundred forty-five million, two hundred seventeen thousand, two hundred eighty-seven".