638406629 has 4 divisors (see below), whose sum is σ = 729607584. Its totient is φ = 547205676.

The previous prime is 638406611. The next prime is 638406649. The reversal of 638406629 is 926604836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638406629 - 2¹² = 638402533 is a prime.

It is a super-2 number, since 2×638406629² = 815126047902287282, which contains 22 as substring.

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 638406629.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638406649) 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, 45600467 + ... + 45600480.

It is an arithmetic number, because the mean of its divisors is an integer number (182401896).

Almost surely, 2^638406629 is an apocalyptic number.

It is an amenable number.

638406629 is a deficient number, since it is larger than the sum of its proper divisors (91200955).

638406629 is an equidigital number, since it uses as much as digits as its factorization.

638406629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91200954.

The product of its (nonzero) digits is 373248, while the sum is 44.

The square root of 638406629 is about 25266.7098966209. The cubic root of 638406629 is about 861.0581121525.

The spelling of 638406629 in words is "six hundred thirty-eight million, four hundred six thousand, six hundred twenty-nine".