638622429 has 4 divisors (see below), whose sum is σ = 851496576. Its totient is φ = 425748284.

The previous prime is 638622403. The next prime is 638622521. The reversal of 638622429 is 924226836.

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 638622429 - 2¹⁵ = 638589661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638621429) 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, 106437069 + ... + 106437074.

It is an arithmetic number, because the mean of its divisors is an integer number (212874144).

Almost surely, 2^638622429 is an apocalyptic number.

It is an amenable number.

638622429 is a deficient number, since it is larger than the sum of its proper divisors (212874147).

638622429 is a wasteful number, since it uses less digits than its factorization.

638622429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212874146.

The product of its digits is 248832, while the sum is 42.

The square root of 638622429 is about 25270.9799770409. The cubic root of 638622429 is about 861.1551221139.

The spelling of 638622429 in words is "six hundred thirty-eight million, six hundred twenty-two thousand, four hundred twenty-nine".