1638193697 has 8 divisors (see below), whose sum is σ = 1874348736. Its totient is φ = 1402570512.

The previous prime is 1638193693. The next prime is 1638193723. The reversal of 1638193697 is 7963918361.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1638193697 - 2² = 1638193693 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638193693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126338 + ... + 138699.

It is an arithmetic number, because the mean of its divisors is an integer number (234293592).

Almost surely, 2^1638193697 is an apocalyptic number.

It is an amenable number.

1638193697 is a deficient number, since it is larger than the sum of its proper divisors (236155039).

1638193697 is an equidigital number, since it uses as much as digits as its factorization.

1638193697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265927.

The product of its digits is 1469664, while the sum is 53.

The square root of 1638193697 is about 40474.6055817719. The cubic root of 1638193697 is about 1178.8405965797.

The spelling of 1638193697 in words is "one billion, six hundred thirty-eight million, one hundred ninety-three thousand, six hundred ninety-seven".