1663906501 has 8 divisors (see below), whose sum is σ = 1763140824. Its totient is φ = 1564823040.

The previous prime is 1663906499. The next prime is 1663906507. The reversal of 1663906501 is 1056093661.

It can be written as a sum of positive squares in 4 ways, for example, as 448338276 + 1215568225 = 21174^2 + 34865^2 .

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 1663906501 - 2¹ = 1663906499 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663906507) 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, 14590 + ... + 59503.

It is an arithmetic number, because the mean of its divisors is an integer number (220392603).

Almost surely, 2^1663906501 is an apocalyptic number.

It is an amenable number.

1663906501 is a deficient number, since it is larger than the sum of its proper divisors (99234323).

1663906501 is a wasteful number, since it uses less digits than its factorization.

1663906501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75431.

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 1663906501 is about 40791.0100512356. The cubic root of 1663906501 is about 1184.9762322020.

The spelling of 1663906501 in words is "one billion, six hundred sixty-three million, nine hundred six thousand, five hundred one".