18729945 has 48 divisors (see below), whose sum is σ = 35420112. Its totient is φ = 9100800.

The previous prime is 18729941. The next prime is 18729959. The reversal of 18729945 is 54992781.

It can be written as a sum of positive squares in 8 ways, for example, as 1115136 + 17614809 = 1056^2 + 4197^2 .

It is not a de Polignac number, because 18729945 - 2² = 18729941 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 18729945.

It is not an unprimeable number, because it can be changed into a prime (18729941) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 58927 + ... + 59243.

It is an arithmetic number, because the mean of its divisors is an integer number (737919).

Almost surely, 2^18729945 is an apocalyptic number.

18729945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18729945 is a deficient number, since it is larger than the sum of its proper divisors (16690167).

18729945 is a wasteful number, since it uses less digits than its factorization.

18729945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442 (or 439 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 18729945 is about 4327.8106474290. The cubic root of 18729945 is about 265.5698902049.

The spelling of 18729945 in words is "eighteen million, seven hundred twenty-nine thousand, nine hundred forty-five".