638901822 has 16 divisors (see below), whose sum is σ = 1376096400. Its totient is φ = 196585152.

The previous prime is 638901817. The next prime is 638901839. The reversal of 638901822 is 228109836.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4095447 + ... + 4095602.

It is an arithmetic number, because the mean of its divisors is an integer number (86006025).

Almost surely, 2^638901822 is an apocalyptic number.

638901822 is an abundant number, since it is smaller than the sum of its proper divisors (737194578).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638901822 is a wasteful number, since it uses less digits than its factorization.

638901822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8191067.

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 638901822 is about 25276.5073141049. The cubic root of 638901822 is about 861.2806869879.

The spelling of 638901822 in words is "six hundred thirty-eight million, nine hundred one thousand, eight hundred twenty-two".