1663798658 has 4 divisors (see below), whose sum is σ = 2495697990. Its totient is φ = 831899328.

The previous prime is 1663798657. The next prime is 1663798681. The reversal of 1663798658 is 8568973661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8568973661 = 137 ⋅62547253.

It can be written as a sum of positive squares in only one way, i.e., 1036646809 + 627151849 = 32197^2 + 25043^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1663798597 and 1663798606.

It is not an unprimeable number, because it can be changed into a prime (1663798651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 415949663 + ... + 415949666.

Almost surely, 2^1663798658 is an apocalyptic number.

1663798658 is a deficient number, since it is larger than the sum of its proper divisors (831899332).

1663798658 is an equidigital number, since it uses as much as digits as its factorization.

1663798658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831899331.

The product of its digits is 13063680, while the sum is 59.

The square root of 1663798658 is about 40789.6881331544. The cubic root of 1663798658 is about 1184.9506309733.

The spelling of 1663798658 in words is "one billion, six hundred sixty-three million, seven hundred ninety-eight thousand, six hundred fifty-eight".