19638978 has 16 divisors (see below), whose sum is σ = 41588640. Its totient is φ = 6161216.

The previous prime is 19638977. The next prime is 19638979. The reversal of 19638978 is 87983691.

It is an interprime number because it is at equal distance from previous prime (19638977) and next prime (19638979).

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 19638978.

It is not an unprimeable number, because it can be changed into a prime (19638977) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96168 + ... + 96371.

It is an arithmetic number, because the mean of its divisors is an integer number (2599290).

Almost surely, 2^19638978 is an apocalyptic number.

19638978 is an abundant number, since it is smaller than the sum of its proper divisors (21949662).

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

19638978 is a wasteful number, since it uses less digits than its factorization.

19638978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192561.

The product of its digits is 653184, while the sum is 51.

The square root of 19638978 is about 4431.5886541961. The cubic root of 19638978 is about 269.7985603111.

The spelling of 19638978 in words is "nineteen million, six hundred thirty-eight thousand, nine hundred seventy-eight".