1663495681 has 8 divisors (see below), whose sum is σ = 1745308928. Its totient is φ = 1583442000.

The previous prime is 1663495663. The next prime is 1663495699. The reversal of 1663495681 is 1865943661.

It is an interprime number because it is at equal distance from previous prime (1663495663) and next prime (1663495699).

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 1663495681 - 2²³ = 1655107073 is a prime.

It is a super-2 number, since 2×1663495681² = 5534435761411307522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1663495621) 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, 437955 + ... + 441736.

It is an arithmetic number, because the mean of its divisors is an integer number (218163616).

Almost surely, 2^1663495681 is an apocalyptic number.

It is an amenable number.

1663495681 is a deficient number, since it is larger than the sum of its proper divisors (81813247).

1663495681 is an equidigital number, since it uses as much as digits as its factorization.

1663495681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879783.

The product of its digits is 933120, while the sum is 49.

The square root of 1663495681 is about 40785.9740719772. The cubic root of 1663495681 is about 1184.8787002783.

The spelling of 1663495681 in words is "one billion, six hundred sixty-three million, four hundred ninety-five thousand, six hundred eighty-one".