1791156645 has 42 divisors (see below), whose sum is σ = 3227211474. Its totient is φ = 953920800.

The previous prime is 1791156611. The next prime is 1791156659. The reversal of 1791156645 is 5466511971.

1791156645 is a `hidden beast` number, since 1 + 79 + 11 + 566 + 4 + 5 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 791521956 + 999634689 = 28134^2 + 31617^2 .

It is not a de Polignac number, because 1791156645 - 2¹⁴ = 1791140261 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1791156645.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 2554795 + ... + 2555495.

Almost surely, 2^1791156645 is an apocalyptic number.

1791156645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1791156645 is a deficient number, since it is larger than the sum of its proper divisors (1436054829).

1791156645 is an frugal number, since it uses more digits than its factorization.

1791156645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1425 (or 709 counting only the distinct ones).

The product of its digits is 226800, while the sum is 45.

The square root of 1791156645 is about 42322.0586101385. The cubic root of 1791156645 is about 1214.4450140226.

Multiplying 1791156645 by its sum of digits (45), we get a square (80602049025 = 283905²).

1791156645 divided by its sum of digits (45) gives a square (39803481 = 6309²).

The spelling of 1791156645 in words is "one billion, seven hundred ninety-one million, one hundred fifty-six thousand, six hundred forty-five".