19981755 has 16 divisors (see below), whose sum is σ = 35523360. Its totient is φ = 10656864.

The previous prime is 19981727. The next prime is 19981757. The reversal of 19981755 is 55718991.

It is not a de Polignac number, because 19981755 - 2⁵ = 19981723 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 19981755.

It is not an unprimeable number, because it can be changed into a prime (19981757) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73872 + ... + 74141.

It is an arithmetic number, because the mean of its divisors is an integer number (2220210).

Almost surely, 2^19981755 is an apocalyptic number.

19981755 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

19981755 is a deficient number, since it is larger than the sum of its proper divisors (15541605).

19981755 is a wasteful number, since it uses less digits than its factorization.

19981755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148027 (or 148021 counting only the distinct ones).

The product of its digits is 113400, while the sum is 45.

The square root of 19981755 is about 4470.0956365608. The cubic root of 19981755 is about 271.3591956318.

It can be divided in two parts, 19981 and 755, that added together give a 4-th power (20736 = 12⁴).

The spelling of 19981755 in words is "nineteen million, nine hundred eighty-one thousand, seven hundred fifty-five".