1971998 has 16 divisors (see below), whose sum is σ = 3425280. Its totient is φ = 833976.

The previous prime is 1971967. The next prime is 1972007. The reversal of 1971998 is 8991791.

It is a super-2 number, since 2×1971998² = 7777552224008, which contains 22 as substring.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215 + ... + 1997.

It is an arithmetic number, because the mean of its divisors is an integer number (214080).

2^1971998 is an apocalyptic number.

1971998 is a deficient number, since it is larger than the sum of its proper divisors (1453282).

1971998 is a wasteful number, since it uses less digits than its factorization.

1971998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1871.

The product of its digits is 40824, while the sum is 44.

The square root of 1971998 is about 1404.2784624141. The cubic root of 1971998 is about 125.4013340687.

The spelling of 1971998 in words is "one million, nine hundred seventy-one thousand, nine hundred ninety-eight".