1998531 has 6 divisors (see below), whose sum is σ = 2886780. Its totient is φ = 1332348.

The previous prime is 1998527. The next prime is 1998533. The reversal of 1998531 is 1358991.

It is a happy number.

It is not a de Polignac number, because 1998531 - 2² = 1998527 is a prime.

It is a super-2 number, since 2×1998531² = 7988252315922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1998533) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 111021 + ... + 111038.

It is an arithmetic number, because the mean of its divisors is an integer number (481130).

2^1998531 is an apocalyptic number.

1998531 is a deficient number, since it is larger than the sum of its proper divisors (888249).

1998531 is a wasteful number, since it uses less digits than its factorization.

1998531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222065 (or 222062 counting only the distinct ones).

The product of its digits is 9720, while the sum is 36.

The square root of 1998531 is about 1413.6940970380. The cubic root of 1998531 is about 125.9612503670.

The spelling of 1998531 in words is "one million, nine hundred ninety-eight thousand, five hundred thirty-one".