1998651 has 8 divisors (see below), whose sum is σ = 2756880. Its totient is φ = 1286432.

The previous prime is 1998643. The next prime is 1998679. The reversal of 1998651 is 1568991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1998651 - 2³ = 1998643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1998611) 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, 11400 + ... + 11573.

It is an arithmetic number, because the mean of its divisors is an integer number (344610).

2^1998651 is an apocalyptic number.

1998651 is a deficient number, since it is larger than the sum of its proper divisors (758229).

1998651 is a wasteful number, since it uses less digits than its factorization.

1998651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23005.

The product of its digits is 19440, while the sum is 39.

The square root of 1998651 is about 1413.7365383974. The cubic root of 1998651 is about 125.9637713933.

The spelling of 1998651 in words is "one million, nine hundred ninety-eight thousand, six hundred fifty-one".