1678421745 has 144 divisors (see below), whose sum is σ = 3976644672. Its totient is φ = 643749120.

The previous prime is 1678421741. The next prime is 1678421779. The reversal of 1678421745 is 5471248761.

It is not a de Polignac number, because 1678421745 - 2² = 1678421741 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1678421745.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1678421741) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 312654 + ... + 317976.

It is an arithmetic number, because the mean of its divisors is an integer number (27615588).

Almost surely, 2^1678421745 is an apocalyptic number.

1678421745 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1678421745 is an abundant number, since it is smaller than the sum of its proper divisors (2298222927).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1678421745 is a wasteful number, since it uses less digits than its factorization.

1678421745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5372 (or 5362 counting only the distinct ones).

The product of its digits is 376320, while the sum is 45.

The square root of 1678421745 is about 40968.5458004064. The cubic root of 1678421745 is about 1188.4120110405.

The spelling of 1678421745 in words is "one billion, six hundred seventy-eight million, four hundred twenty-one thousand, seven hundred forty-five".