19998738 has 20 divisors (see below), whose sum is σ = 44812350. Its totient is φ = 6666192.

The previous prime is 19998733. The next prime is 19998743. The reversal of 19998738 is 83789991.

It is an interprime number because it is at equal distance from previous prime (19998733) and next prime (19998743).

It can be written as a sum of positive squares in only one way, i.e., 16184529 + 3814209 = 4023^2 + 1953^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (19998733) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 61563 + ... + 61886.

Almost surely, 2^19998738 is an apocalyptic number.

19998738 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19998738 is an abundant number, since it is smaller than the sum of its proper divisors (24813612).

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

19998738 is a wasteful number, since it uses less digits than its factorization.

19998738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123463 (or 123454 counting only the distinct ones).

The product of its digits is 979776, while the sum is 54.

The square root of 19998738 is about 4471.9948568843. The cubic root of 19998738 is about 271.4360522143.

It can be divided in two parts, 19998 and 738, that added together give a 4-th power (20736 = 12⁴).

The spelling of 19998738 in words is "nineteen million, nine hundred ninety-eight thousand, seven hundred thirty-eight".