1663887951 has 12 divisors (see below), whose sum is σ = 2621884200. Its totient is φ = 1008416880.

The previous prime is 1663887947. The next prime is 1663887977. The reversal of 1663887951 is 1597883661.

It is not a de Polignac number, because 1663887951 - 2² = 1663887947 is a prime.

It is a super-2 number, since 2×1663887951² = 5537046226965956802, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663887991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8403376 + ... + 8403573.

It is an arithmetic number, because the mean of its divisors is an integer number (218490350).

Almost surely, 2^1663887951 is an apocalyptic number.

1663887951 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1663887951 is a deficient number, since it is larger than the sum of its proper divisors (957996249).

1663887951 is a wasteful number, since it uses less digits than its factorization.

1663887951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16806966 (or 16806963 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The square root of 1663887951 is about 40790.7826720694. The cubic root of 1663887951 is about 1184.9718286311.

The spelling of 1663887951 in words is "one billion, six hundred sixty-three million, eight hundred eighty-seven thousand, nine hundred fifty-one".