1663634651 has 4 divisors (see below), whose sum is σ = 1901296752. Its totient is φ = 1425972552.

The previous prime is 1663634593. The next prime is 1663634659. The reversal of 1663634651 is 1564363661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1663634651 - 2⁶ = 1663634587 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1663634599 and 1663634608.

It is not an unprimeable number, because it can be changed into a prime (1663634659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 118831040 + ... + 118831053.

It is an arithmetic number, because the mean of its divisors is an integer number (475324188).

Almost surely, 2^1663634651 is an apocalyptic number.

1663634651 is a deficient number, since it is larger than the sum of its proper divisors (237662101).

1663634651 is an equidigital number, since it uses as much as digits as its factorization.

1663634651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237662100.

The product of its digits is 233280, while the sum is 41.

The square root of 1663634651 is about 40787.6776857913. The cubic root of 1663634651 is about 1184.9116946547.

The spelling of 1663634651 in words is "one billion, six hundred sixty-three million, six hundred thirty-four thousand, six hundred fifty-one".