1998517481 has 16 divisors (see below), whose sum is σ = 2071818000. Its totient is φ = 1926832128.

The previous prime is 1998517463. The next prime is 1998517483. The reversal of 1998517481 is 1847158991.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 38241856 + 1960275625 = 6184^2 + 44275^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1998517481 is a prime.

It is a super-2 number, since 2×1998517481² = 7988144243725170722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1998517483) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 764705 + ... + 767313.

It is an arithmetic number, because the mean of its divisors is an integer number (129488625).

Almost surely, 2^1998517481 is an apocalyptic number.

It is an amenable number.

1998517481 is a deficient number, since it is larger than the sum of its proper divisors (73300519).

1998517481 is a wasteful number, since it uses less digits than its factorization.

1998517481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2908.

The product of its digits is 725760, while the sum is 53.

The square root of 1998517481 is about 44704.7814109408. The cubic root of 1998517481 is about 1259.6096634603.

The spelling of 1998517481 in words is "one billion, nine hundred ninety-eight million, five hundred seventeen thousand, four hundred eighty-one".