637649371 has 4 divisors (see below), whose sum is σ = 640317600. Its totient is φ = 634981144.

The previous prime is 637649359. The next prime is 637649381. The reversal of 637649371 is 173946736.

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 637649371 - 2⁵ = 637649339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (637649351) 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 3 ways as a sum of consecutive naturals, for example, 1333756 + ... + 1334233.

It is an arithmetic number, because the mean of its divisors is an integer number (160079400).

Almost surely, 2^637649371 is an apocalyptic number.

637649371 is a deficient number, since it is larger than the sum of its proper divisors (2668229).

637649371 is a wasteful number, since it uses less digits than its factorization.

637649371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2668228.

The product of its digits is 571536, while the sum is 46.

The square root of 637649371 is about 25251.7201592288. The cubic root of 637649371 is about 860.7175240407.

The spelling of 637649371 in words is "six hundred thirty-seven million, six hundred forty-nine thousand, three hundred seventy-one".