1663701637 has 4 divisors (see below), whose sum is σ = 1791678700. Its totient is φ = 1535724576.

The previous prime is 1663701631. The next prime is 1663701661. The reversal of 1663701637 is 7361073661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7361073661 = 17 ⋅433004333.

It can be written as a sum of positive squares in 2 ways, for example, as 511031236 + 1152670401 = 22606^2 + 33951^2 .

It is a cyclic number.

It is not a de Polignac number, because 1663701637 - 2¹¹ = 1663699589 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1663701637.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663701631) 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, 63988512 + ... + 63988537.

It is an arithmetic number, because the mean of its divisors is an integer number (447919675).

Almost surely, 2^1663701637 is an apocalyptic number.

It is an amenable number.

1663701637 is a deficient number, since it is larger than the sum of its proper divisors (127977063).

1663701637 is a wasteful number, since it uses less digits than its factorization.

1663701637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127977062.

The product of its (nonzero) digits is 95256, while the sum is 40.

The square root of 1663701637 is about 40788.4988323915. The cubic root of 1663701637 is about 1184.9275978719.

The spelling of 1663701637 in words is "one billion, six hundred sixty-three million, seven hundred one thousand, six hundred thirty-seven".