19997078 has 4 divisors (see below), whose sum is σ = 29995620. Its totient is φ = 9998538.

The previous prime is 19997071. The next prime is 19997093. The reversal of 19997078 is 87079991.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19997071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999268 + ... + 4999271.

It is an arithmetic number, because the mean of its divisors is an integer number (7498905).

Almost surely, 2^19997078 is an apocalyptic number.

19997078 is a deficient number, since it is larger than the sum of its proper divisors (9998542).

19997078 is an equidigital number, since it uses as much as digits as its factorization.

19997078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9998541.

The product of its (nonzero) digits is 285768, while the sum is 50.

The square root of 19997078 is about 4471.8092535349. The cubic root of 19997078 is about 271.4285418019.

The spelling of 19997078 in words is "nineteen million, nine hundred ninety-seven thousand, seventy-eight".