19997982 has 32 divisors (see below), whose sum is σ = 45645600. Its totient is φ = 6485184.

The previous prime is 19997963. The next prime is 19997993. The reversal of 19997982 is 28979991.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3007 + ... + 7002.

It is an arithmetic number, because the mean of its divisors is an integer number (1426425).

Almost surely, 2^19997982 is an apocalyptic number.

19997982 is an abundant number, since it is smaller than the sum of its proper divisors (25647618).

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

19997982 is a wasteful number, since it uses less digits than its factorization.

19997982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10057 (or 10051 counting only the distinct ones).

The product of its digits is 734832, while the sum is 54.

The square root of 19997982 is about 4471.9103300491. The cubic root of 19997982 is about 271.4326318612.

Subtracting 19997982 from its reverse (28979991), we obtain a square (8982009 = 2997²).

It can be divided in two parts, 19 and 997982, that added together give a square (998001 = 999²).

The spelling of 19997982 in words is "nineteen million, nine hundred ninety-seven thousand, nine hundred eighty-two".